[FLINK-17255][python] Add HBase connector descriptor support in PyFlink.

[shuiqiangchen]

What is the purpose of the change

HBase connector descriptor is already supported since 1.10.0 at Java side. We should also support it in PyFlink.

Brief change log

• add HBase connector descriptor methods corresponding to java side in descriptors.py
• add HBaseDescriptorTests in test_descriptors.py
• add HBase connector usage documentation in connect.md

Verifying this change

This change added tests and can be verified as follows:

• added HBaseDescriptorTests in test_descriptors.py

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/Mesos, ZooKeeper: (no)
• The S3 file system connector: (no)

Documentation

• Does this pull request introduce a new feature? ( no)

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Automated Checks

Last check on commit 66b1693 (Thu Apr 30 06:20:30 UTC 2020)

Warnings:

• Documentation files were touched, but no .zh.md files: Update Chinese documentation or file Jira ticket.
• This pull request references an unassigned Jira ticket. According to the code contribution guide, tickets need to be assigned before starting with the implementation work.

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Review Progress

• ❓ 1. The [description] looks good.
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• ❓ 3. Needs [attention] from.
• ❓ 4. The change fits into the overall [architecture].
• ❓ 5. Overall code [quality] is good.

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CI report:

• a8148a8 UNKNOWN
• cca7863 Azure: SUCCESS

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[dianfu]

@flinkbot run azure

[dianfu]

@zentol Do you know why the CI was not triggered even manually triggered with @flinkbot run azure?

[dianfu]

@flinkbot run azure

[shuiqiangchen]

@flinkbot run azure

[dianfu]

@shuiqiangchen Thanks for the PR. LGTM. Merging...