[FLINK-39188][docs] Documentation for BITMAP type

[dylanhz]

What is the purpose of the change

Adds documentation for the BITMAP data type (FLIP-556).

Brief change log

• Added BITMAP type documentation to data-types.md
• Added performance tips for bitmap aggregate functions
• Updated both English and Chinese documentation

Verifying this change

This change is a documentation update without any test coverage.

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: no

Documentation

• Does this pull request introduce a new feature? no
• If yes, how is the feature documented? not applicable

[flinkbot]

CI report:

• fabee6d Azure: SUCCESS

Bot commands

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

[lincoln-lil]

Thanks @dylanhz for the high-quality documentation with both en & zh version!
Checked the doc page locally, all contents looks fine and links works.