Added support for setting the framework using the public api (#1908)

[tobiasstadler]

What does this PR do?

Fixes #1908

Checklist

• This is an enhancement of existing features, or a new feature in existing plugins
  • I have updated CHANGELOG.asciidoc
  • I have added tests that prove my fix is effective or that my feature works
  • Added an API method or config option? Document in which version this will be introduced
  • I have made corresponding changes to the documentation

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• Start Time: 2021-07-13T09:33:00.958+0000

• Duration: 53 min 19 sec

• Commit: 8dec8e5

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Total	2368

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[eyalkoren]

Thanks for this PR @tobiasstadler !

Some things are missing:

1. document the added API to docs/public-api.asciidoc
2. providing higher precedence to user-set values, both is set before AND after the automatic setting
3. the implementation of 2 should include the ability to set null or empty string in order to override the automatically-set value
4. testing 2 and 3 - before/after automatic, with null/empty and valid value
5. extend the javadoc and asciidoc to specify the above

You can see examples for all of those in #1788

[tobiasstadler]

@eyalkoren I did the requested changes

The javadoc/documentation states

Override the name of the framework for the current transaction.
For supported frameworks,
the framework name is determined automatically,
and can be overridden using this function.

In my opinion this clearly says that a user set value has a higher precedence that an automatic set value (by a plugin). Do you agree?

[eyalkoren]

In my opinion this clearly says that a user set value has a higher precedence that an automatic set value (by a plugin). Do you agree?

Absolutely agree, only a word that setting null or empty value will make the agent omit this field, just as a clarification

[eyalkoren]

run elasticsearch-ci/docs

[tobiasstadler]

Thank You!

[eyalkoren]

Thank YOU! 😄