Enable incremental processing for ModuleProviderGenerator.

[pengdev]

For reference: https://docs.gradle.org/current/userguide/java_plugin.html#sec:incremental_annotation_processing

Starting with Gradle 4.7, the incremental compiler also supports incremental annotation processing. All annotation processors need to opt in to this feature, otherwise they will trigger a full recompilation.

The whole Gradle module will be non-incremental if there is just one non-incremental annotation processor. We need to make sure that all annotation processors in the module support incremental kapt.

This PR adds incremental annotation processing support to ModuleProviderGenerator. More specifically, it makes ModuleProviderGenerator an isolating annotation processor. This PR also introduces https://github.com/tbroyer/gradle-incap-helper as compile dependency to generate the META-INF descriptor.

cc @LukasPaczos @tobrun

[pengdev]

Validated with building examples project and modify the MyLogger class's MapboxModule annotation and see the following output:

[INFO] Kapt3 is enabled (stand-alone mode).
Annotation processing mode: apt
Memory leak detection mode: none
Show processor time: false
Verbose mode: true
Info as warnings: false
Use light analysis: false
Correct error types: false
Dump default parameter values: false
Map diagnostic locations: false
Strict mode: false
Detect annotation processors in compile classpath: true
Incremental annotation processing (apt mode): true
Project base dir: /Users/pengliu/Documents/mapbox-base-android/examples
Compile classpath: 
...
Sources output directory: /Users/pengliu/Documents/mapbox-base-android/examples/build/generated/source/kapt/debug
Class files output directory: /Users/pengliu/Documents/mapbox-base-android/examples/build/tmp/kapt3/classes/debug
Stubs output directory: /Users/pengliu/Documents/mapbox-base-android/examples/build/tmp/kapt3/stubs/debug
Incremental data output directory: /Users/pengliu/Documents/mapbox-base-android/examples/build/tmp/kapt3/stubs/debug
Annotation processing classpath: /Users/pengliu/Documents/mapbox-base-android/annotations-processor/build/libs/annotations-processor-0.7.0-SNAPSHOT.jar, /Users/pengliu/Documents/mapbox-base-android/annotations/build/libs/annotations-0.7.0-SNAPSHOT.jar, /Users/pengliu/.gradle/caches/modules-2/files-2.1/com.squareup/kotlinpoet/1.6.0/6ce4c42da0daf2ba11a4180d33360e8c049ef5b8/kotlinpoet-1.6.0.jar, /Users/pengliu/.gradle/caches/modules-2/files-2.1/org.jetbrains.kotlin/kotlin-stdlib-jdk8/1.3.72/916d54b9eb6442b615e6f1488978f551c0674720/kotlin-stdlib-jdk8-1.3.72.jar, /Users/pengliu/.gradle/caches/modules-2/files-2.1/org.jetbrains.kotlin/kotlin-stdlib-jdk7/1.4.10/30e46450b0bb3dbf43898d2f461be4a942784780/kotlin-stdlib-jdk7-1.4.10.jar, /Users/pengliu/.gradle/caches/modules-2/files-2.1/com.google.auto.service/auto-service/1.0-rc7/894e4af172edf98872bf87f5a90912f86f3e9158/auto-service-1.0-rc7.jar, /Users/pengliu/.gradle/caches/modules-2/files-2.1/androidx.annotation/annotation/1.1.0/e3a6fb2f40e3a3842e6b7472628ba4ce416ea4c8/annotation-1.1.0.jar, /Users/pengliu/.gradle/caches/modules-2/files-2.1/org.jetbrains.kotlin/kotlin-reflect/1.3.72/86613e1a669a701b0c660bfd2af4f82a7ae11fca/kotlin-reflect-1.3.72.jar, /Users/pengliu/.gradle/caches/modules-2/files-2.1/org.jetbrains.kotlin/kotlin-stdlib/1.4.10/ea29e063d2bbe695be13e9d044dcfb0c7add398e/kotlin-stdlib-1.4.10.jar, /Users/pengliu/.gradle/caches/modules-2/files-2.1/com.google.auto.service/auto-service-annotations/1.0-rc7/8849037b03b10cd3d71cce67f8b99aed183971cb/auto-service-annotations-1.0-rc7.jar, /Users/pengliu/.gradle/caches/modules-2/files-2.1/com.google.auto/auto-common/0.10/c8f153ebe04a17183480ab4016098055fb474364/auto-common-0.10.jar, /Users/pengliu/.gradle/caches/modules-2/files-2.1/com.google.guava/guava/27.0.1-jre/bd41a290787b5301e63929676d792c507bbc00ae/guava-27.0.1-jre.jar, /Users/pengliu/.gradle/caches/modules-2/files-2.1/org.jetbrains.kotlin/kotlin-stdlib-common/1.4.10/6229be3465805c99db1142ad75e6c6ddeac0b04c/kotlin-stdlib-common-1.4.10.jar, /Users/pengliu/.gradle/caches/modules-2/files-2.1/org.jetbrains/annotations/13.0/919f0dfe192fb4e063e7dacadee7f8bb9a2672a9/annotations-13.0.jar, /Users/pengliu/.gradle/caches/modules-2/files-2.1/com.google.guava/failureaccess/1.0.1/1dcf1de382a0bf95a3d8b0849546c88bac1292c9/failureaccess-1.0.1.jar, /Users/pengliu/.gradle/caches/modules-2/files-2.1/com.google.guava/listenablefuture/9999.0-empty-to-avoid-conflict-with-guava/b421526c5f297295adef1c886e5246c39d4ac629/listenablefuture-9999.0-empty-to-avoid-conflict-with-guava.jar, /Users/pengliu/.gradle/caches/modules-2/files-2.1/com.google.code.findbugs/jsr305/3.0.2/25ea2e8b0c338a877313bd4672d3fe056ea78f0d/jsr305-3.0.2.jar, /Users/pengliu/.gradle/caches/modules-2/files-2.1/org.checkerframework/checker-qual/2.5.2/cea74543d5904a30861a61b4643a5f2bb372efc4/checker-qual-2.5.2.jar, /Users/pengliu/.gradle/caches/modules-2/files-2.1/com.google.errorprone/error_prone_annotations/2.2.0/88e3c593e9b3586e1c6177f89267da6fc6986f0c/error_prone_annotations-2.2.0.jar, /Users/pengliu/.gradle/caches/modules-2/files-2.1/com.google.j2objc/j2objc-annotations/1.1/ed28ded51a8b1c6b112568def5f4b455e6809019/j2objc-annotations-1.1.jar, /Users/pengliu/.gradle/caches/modules-2/files-2.1/org.codehaus.mojo/animal-sniffer-annotations/1.17/f97ce6decaea32b36101e37979f8b647f00681fb/animal-sniffer-annotations-1.17.jar
Annotation processors: 
AP options: {kapt.kotlin.generated=/Users/pengliu/Documents/mapbox-base-android/examples/build/generated/source/kaptKotlin/debug}
Javac options: {-source=1.7}
[incremental apt] Changed files: [/Users/pengliu/Documents/mapbox-base-android/examples/build/tmp/kapt3/stubs/debug/com/mapbox/common/examples/MyLogger.java]
[incremental apt] Compiled sources directories: /Users/pengliu/Documents/mapbox-base-android/examples/build/tmp/kotlin-classes/debug, /Users/pengliu/Documents/mapbox-base-android/examples/build/intermediates/javac/debug/classes
[incremental apt] Cache directory for incremental compilation: /Users/pengliu/Documents/mapbox-base-android/examples/build/tmp/kapt3/incApCache/debug
[incremental apt] Changed classpath names: 

[INFO] Need to discovery annotation processors in the AP classpath
[INFO] Annotation processors: com.mapbox.annotation.processor.ModuleProviderGenerator, com.google.auto.service.processor.AutoServiceProcessor
[INFO] Processing java sources with annotation processors: /Users/pengliu/Documents/mapbox-base-android/examples/build/tmp/kapt3/stubs/debug/com/mapbox/common/examples/MyLogger.java, /Users/pengliu/Documents/mapbox-base-android/examples/build/tmp/kapt3/stubs/debug/error/NonExistentClass.java
Note: Generating module configuration class for com.mapbox.common.examples.MyLogger[INFO] Analyzing sources structure took 1[ms].
[INFO] Annotation processing complete, errors: 0, warnings: 0
[INFO] Annotation processor stats:
[INFO] com.mapbox.annotation.processor.ModuleProviderGenerator: total: 120 ms, init: 17 ms, 2 round(s): 103 ms, 0 ms
[INFO] com.google.auto.service.processor.AutoServiceProcessor: total: 4 ms, init: 4 ms, 0 round(s): 
File Object History : []
Open Type Names     : []
Gen. Src Names      : []
Gen. Cls Names      : []
Agg. Gen. Src Names : []
Agg. Gen. Cls Names : []
[INFO] Annotation processing took 155 ms