add oceanbasecdc connector

[whhe]

Purpose of this pull request

Add OceanBase CDC connector.

Which issue you fix

Close #702.

Note that there are still some work to do:

1. Implement OceanBaseCdcColumnConverter.createInternalConverter. The type of log message is not in one-to-one correspondence with the type of flink, so we can't run the json sync task without column and transformer for now.
2. Resolve protobuf-java version conflicts. The oblogclient used in OceanBase CDC connector depends on protobuf-java-3.18.2, while other packages depend on protobuf-java-2.5.0, so we can only test the connector using shell (with stream connector) but not in the local-test module (with all connectors) for now.
3. Add more tests for all types conversion.

I think these issues can be resolved later, and I would love to contribute for it.

Checklist:

• I have executed the 'mvn spotless:apply' command to format my code.
• I have a meaningful commit message (including the issue id, the template of commit message is '[label-type-#issue-id][fixed-module] a meaningful commit message.')
• I have performed a self-review of my own code.
• I have commented my code, particularly in hard-to-understand areas.
• I have made corresponding changes to the documentation.
• I have added tests that prove my fix is effective or that my feature works.
• New and existing unit tests pass locally with my changes.
• I have checked my code and corrected any misspellings.
• My commit is only one. (If there are multiple commits, you can use 'git squash' to compress multiple commits into one.)

[FlechazoW]

Please add apache license.

[ll076110]

Thank you for the PR, I think there is no problem with the merge, can you provide a usage document?

[whhe]

Thank you for the PR, I think there is no problem with the merge, can you provide a usage document?

Should I append the doc in this pr or provide it in a new one?

[FlechazoW]

Thank you for the PR, I think there is no problem with the merge, can you provide a usage document?

Should I append the doc in this pr or provide it in a new one?

I think it would be better to add the documentation to this pr.

[whhe]

Thank you for the PR, I think there is no problem with the merge, can you provide a usage document?

Should I append the doc in this pr or provide it in a new one?

I think it would be better to add the documentation to this pr.

Doc added.