[FLINK-18416][table-common] Deprecate TableEnvironment#connect API

[wuchong]

What is the purpose of the change

In the past releases, the community focused on the new SQL DDL features and the TableEnvironment#connect API is not maintained for a long time. We have seen many (bug) issues around this APIs.

The TableEnvironment#connect() API might receive some refactoring in the next release. So we should deprecate the connect API in 1.11 and recommend users to use executeSql(ddl) instead. Thus, we can remove/refactor the existing connect() API in the next release even though it is API breaking.

Brief change log

• deprecate all the existing connect() API and add deprecate Javadoc.

Verifying this change

N/A.

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

• Dependencies (does it add or upgrade a dependency): (yes / no)
• The public API, i.e., is any changed class annotated with @Public(Evolving): (yes / no)
• The serializers: (yes / no / don't know)
• The runtime per-record code paths (performance sensitive): (yes / no / don't know)
• Anything that affects deployment or recovery: JobManager (and its components), Checkpointing, Yarn/Mesos, ZooKeeper: (yes / no / don't know)
• The S3 file system connector: (yes / no / don't know)

Documentation

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

[twalthr]

Makes sense to me. I added a comment about the wording.

[twalthr]

It would be nice to answer the why? question for users. E.g. The SQL {@code CREATE TABLE} DDL is richer than this part of the API. This method might be refactored in the next versions. Please use {@link #executeSql(String) executeSql(ddl)} to register a table instead.

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Automated Checks

Last check on commit 7260e8b (Tue Jun 23 10:42:33 UTC 2020)

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[wuchong]

Build is passed in my repo: https://dev.azure.com/imjark/Flink/_build/results?buildId=186&view=results

Merging...