MODULES-8699: Add option to manage symlink

[fraenki]

https://tickets.puppetlabs.com/browse/MODULES-8699

This adds the capability to java::oracle to manage a symlink for this version, which will point to the Java installation directory. This is useful because it adds a static path that will never change, no matter which Java version is currently in use.

java::oracle { 'jdk8':
  basedir => '/mnt'
  java_se => 'jdk'
  version_major => '8u201'
  version_minor => 'b09'
  url_hash => '42970487e3af4f5aa5bca3f542482c60'
  package_type => 'tar.gz'
  manage_symlink => true
  symlink_name => 'java_home'
}

Info: Applying configuration version '1551101640'
Notice: /Stage[main]/Java::Oracle[jdk8]/Archive[/tmp/jdk-8u201-linux-x64.tar.gz]/ensure: download archive from [...]
Notice: /Stage[main]/Java::Oracle[jdk8]/Exec[Install Oracle java_se jdk 8 8u201 b09]/returns: executed successfully
Notice: /Stage[main]/Java::Oracle[jdk8]/File[/mnt/java_home]/ensure: created

This feature is also available in puppet-jdk_oracle, which is no longer maintained and suggests to use puppetlabs-java instead.

I've added a test for this too:

java::oracle
  with CentOS 64-bit
    ...
    when manage_symlink is set to true
      should contain File[/usr/java/java_home]
    ...

[david22swan]

Have run the change through an adhoc pipeline and the changes themselves look good to me.

[david22swan]

@fraenki Thanks for putting in the work on this. Will try to get to your other PR soon.