Expend coverage for default mapping for prometheus emitter

[ztzxt]

Description

Went over https://druid.apache.org/docs/latest/operations/metrics/ and added most of missing metrics to prometheus emitter default mapping.

This PR has:

• been self-reviewed.
• added documentation for new or modified features or behaviors.
• a release note entry in the PR description.
• added Javadocs for most classes and all non-trivial methods. Linked related entities via Javadoc links.
• added or updated version, license, or notice information in licenses.yaml
• added comments explaining the "why" and the intent of the code wherever would not be obvious for an unfamiliar reader.
• added unit tests or modified existing tests to cover new code paths, ensuring the threshold for code coverage is met.
• added integration tests.
• been tested in a test Druid cluster.

[ztzxt]

We ended up expanding the current default mapping for prometheus-emitter. Therefore decided to share it with the upstream. When deciding between gauge/count types, I used similar (and already existing) metrics as an example. I didn't add the metric if it required some module unless the Prometheus metric was already generated with the default configuration. I re-ordered the existing metrics so they'd reflect the order in the document. I also removed the non-existent metrics such as segment/cost/*

diff for added/removed metric names:

cat extensions-contrib/prometheus-emitter/src/main/resources/defaultMetrics.json| jq -r 'keys[]' | sort > feature-metrics
git checkout master 
cat extensions-contrib/prometheus-emitter/src/main/resources/defaultMetrics.json| jq -r 'keys[]' | sort > master-metrics 
diff master-metrics feature-metrics 
0a1,6
> compact/segmentAnalyzer/fetchAndProcessMillis
> compact/task/count
> compactTask/availableSlot/count
> compactTask/maxSlot/count
> coordinator/global/time
> coordinator/time
2a9,10
> ingest/bytes/received
> ingest/count
9a18
> ingest/handoff/count
10a20,21
> ingest/handoff/time
> ingest/input/bytes
17a29,30
> ingest/notices/time
> ingest/pause/time
23a37,50
> ingest/segments/count
> ingest/sink/count
> ingest/tombstones/count
> interval/compacted/count
> interval/skipCompact/count
> interval/waitCompact/count
> jetty/numOpenConnections
> jetty/threadPool/busy
> jetty/threadPool/idle
> jetty/threadPool/isLowOnThreads
> jetty/threadPool/max
> jetty/threadPool/min
> jetty/threadPool/queueSize
> jetty/threadPool/total
36a64,67
> kill/pendingSegments/count
> kill/task/count
> killTask/availableSlot/count
> killTask/maxSlot/count
37a69,79
> metadata/kill/audit/count
> metadata/kill/compaction/count
> metadata/kill/datasource/count
> metadata/kill/rule/count
> metadata/kill/supervisor/count
> metadatacache/init/time
> metadatacache/refresh/count
> metadatacache/refresh/time
> metadatacache/schemaPoll/count
> metadatacache/schemaPoll/failed
> metadatacache/schemaPoll/time
45a88,90
> query/cache/delta/put/error
> query/cache/delta/put/ok
> query/cache/delta/put/oversized
54a100,102
> query/cache/total/put/error
> query/cache/total/put/ok
> query/cache/total/put/oversized
61d108
< query/intervalChunk/time
72a120
> segment/assignSkipped/count
74,76c122,123
< segment/cost/normalization
< segment/cost/normalized
< segment/cost/raw
---
> segment/compacted/bytes
> segment/compacted/count
79a127
> segment/dropSkipped/count
80a129,130
> segment/loadQueue/assigned
> segment/loadQueue/cancelled
83a134
> segment/loadQueue/success
84a136
> segment/moveSkipped/count
92a145,146
> segment/skipCompact/bytes
> segment/skipCompact/count
95a150
> segment/unneededEternityTombstone/count
97a153,157
> segment/waitCompact/bytes
> segment/waitCompact/count
> serverview/init/time
> serverview/sync/healthy
> serverview/sync/unstableTime
98a159,161
> sqlQuery/bytes
> sqlQuery/planningTimeMs
> sqlQuery/time
99a163
> sys/disk/queue
101a166
> sys/disk/transferTime
103a169,170
> sys/fs/files/count
> sys/fs/files/free
105a173,176
> sys/mem/free
107a179,181
> sys/net/read/dropped
> sys/net/read/errors
> sys/net/read/packets
108a183,185
> sys/net/write/collisions
> sys/net/write/errors
> sys/net/write/packets
114a192,209
> sys/tcpv4/activeOpens
> sys/tcpv4/attemptFails
> sys/tcpv4/estabResets
> sys/tcpv4/in/errs
> sys/tcpv4/in/segs
> sys/tcpv4/out/rsts
> sys/tcpv4/out/segs
> sys/tcpv4/passiveOpens
> sys/tcpv4/retrans/segs
> sys/uptime
> task/action/batch/attempts
> task/action/batch/queueTime
> task/action/batch/runTime
> task/action/batch/size
> task/action/failed/count
> task/action/log/time
> task/action/run/time
> task/action/success/count
116a212
> task/pending/time
118a215
> task/segmentAvailability/wait/time
120a218,221
> tier/historical/count
> tier/replication/factor
> tier/required/capacity
> tier/total/capacity
121a223
> zk/reconnect/time

[cryptoe]

Changes lgtm.
Thanks @ztzxt .
There are a few more metrics which will be added as part of druid 30.
It would be lovely if you can patch that up as well :)

[cryptoe]

All druid metrics are present here : https://github.com/apache/druid/commits/master/docs/operations/metrics.md