[GOBBLIN-2183] Add COMPILED & RUNNING events to GaSJobObservabilityEventProducer

[iPalash]

Dear Gobblin maintainers,

Please accept this PR. I understand that it will not be reviewed until I have checked off all the steps below!

JIRA

• My PR addresses the following Gobblin JIRA issues and references them in the PR title. For example,
  • https://issues.apache.org/jira/browse/GOBBLIN-2183

Description

• Here are some details about my PR, including screenshots (if applicable):

Currently only terminal events (failed, complete & cancelled) are emitted by GaSJobObservabilityEventProducer. This PR adds COMPILED and RUNNING events to the producer providing visibility into stuck flows/job. It also enables us to derive metrics like realtime scheduling/execution delays as compared to now where we can derive that only after the terminal event is emitted.

Tests

• My PR adds the following unit tests OR does not need testing for this extremely good reason:

Modified existing tests in KafkaAvroJobStatusMonitorTest to check for the newly added events.

Commits

• My commits all reference JIRA issues in their subject lines, and I have squashed multiple commits if they address the same issue. In addition, my commits follow the guidelines from "How to write a good git commit message":
  1. Subject is separated from body by a blank line
  2. Subject is limited to 50 characters
  3. Subject does not end with a period
  4. Subject uses the imperative mood ("add", not "adding")
  5. Body wraps at 72 characters
  6. Body explains "what" and "why", not "how"