[FLINK-25795][python][connector/pulsar] Add pulsar sink DataStream API

[a49a]

What is the purpose of the change

There is no python pulsar sink API.

Brief change log

Add python pulsar sink.

Verifying this change

This change added tests and can be verified as follows:

(example:)

• Added test that validates sink configuration

Does this pull request potentially affect one of the following parts:

• Dependencies (does it add or upgrade a dependency): (no)
• The public API, i.e., is any changed class annotated with @Public(Evolving): no)
• The serializers: (no)
• The runtime per-record code paths (performance sensitive): (no)
• Anything that affects deployment or recovery: JobManager (and its components), Checkpointing, Kubernetes/Yarn, ZooKeeper: (no)
• The S3 file system connector: (n )

Documentation

• Does this pull request introduce a new feature? (yes)
• If yes, how is the feature documented? (PyDocs)

[flinkbot]

CI report:

• 4d15293 Azure: SUCCESS

Bot commands

The @flinkbot bot supports the following commands:

• @flinkbot run azure re-run the last Azure build

[dianfu]

@deadwind4 Thanks for the PR. Have left a few comments. Besides, we should also update the documentation in https://nightlies.apache.org/flink/flink-docs-master/docs/connectors/datastream/pulsar/ by adding Python examples.

[dianfu]

@deadwind4 Thanks a lot for the update. Have left a few comments. Besides, it seems that the tests didn't passed and there are checkstyle issues. You could run check style check locally under directory flink-python as following: ./dev/lint-python.sh sphinx

[dianfu]

@deadwind4 Thanks for the update. LGTM overall.

[dianfu]

Suggested change

	>>> sink = PulsarSink() \\
	>>> sink = PulsarSink \\