[FLINK-29434] Add AlgoOperator for Splitter

[weibozhao]

What is the purpose of the change

This pull request Add AlgoOperator for Splitter.

Brief change log

• Adds Add AlgoOperator for Splitter in Java and Python
• Adds examples and documentations of Splitter

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): (yes)

Documentation

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