[FLINK-14319][api] Register user jar files in execution environment.

[mr-cloud]

What is the purpose of the change

Add interfaces in {Stream}ExecutionEnviroment to allow people to register user jar files in an execution environment.

Brief change log

• Add interface registerUserJarFile() for StreamExecutionEnvironment both for Java and Scala API.
• Add interface registerUserJarFile() for ExecutionEnvironment both for Java and Scala API.

Verifying this change

This change added tests and can be verified as follows:

• User jar in local can be tested with AddingUserJarTest.java.
• User jar in a distributed file system like HDFS can be tested with UserJarDfsTest.java.

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

Documentation

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

[flinkbot]

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Automated Checks

Last check on commit a9d0502 (Wed Oct 16 08:38:32 UTC 2019)

Warnings:

• 2 pom.xml files were touched: Check for build and licensing issues.
• No documentation files were touched! Remember to keep the Flink docs up to date!
• 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.
• ❓ 2. There is [consensus] that the contribution should go into to Flink.
• ❓ 3. Needs [attention] from.
• ❓ 4. The change fits into the overall [architecture].
• ❓ 5. Overall code [quality] is good.

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[flinkbot]

CI report:

• 3560d8f : FAILURE Build
• c0d1e30 : FAILURE Build
• 30c6aa7 : FAILURE Build
• 11e6602 : FAILURE Build
• a9d0502 : FAILURE Build

[mr-cloud]

The CI reports a build failure because of the lack of licenses for some files. I added licenses for them now. Please continue :-). @rmetzger

[mr-cloud]

All parts of the building are successful except that python APICompletenessTestCases for {Stream}ExecutionEnvironment failed as missing the API declared in Java's. Maybe we can implement the APIs for python in another issue. What's your option? @rmetzger @HuangZhenQiu

[zentol]

Please wait for consent of the community before opening a PR.

[mr-cloud]

Thanks. The PR is closed for now. And I proposed a plan detail for design and testing. Let's discuss first. Please review that and vote for this issue if it's reasonable. @zentol @HuangZhenQiu @rmetzger
issue address: https://issues.apache.org/jira/browse/FLINK-14319