[Issue #3810][pulsar-broker] Implement configurable token auth claim

[klevy-toast]

Resolves #3810

Please let me know if I've missed anything!

Motivation

This change allows more configuration of the AuthenticationTokenProvider, so that the user can specify which "claim" that is attached to the token should be used as the "role". Before, it was hard-coded in to use the token's subject claim ("sub").

Modifications

Added a field to the AuthenticationTokenProvider which controls which claim is returned from parseToken, and a method that sets that field based on the .conf file. Added some documentation and a test.

Verifying this change

• Make sure that the change passes the CI checks.

This change added tests and can be verified as follows:

• Added unit test to AuthenticationTokenProviderTest which sets the configuration and verifies that it picks up the right value

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

If yes was chosen, please highlight the changes

• Dependencies (does it add or upgrade a dependency): (no)
• The public API: (no)
• The schema: (no)
• The default values of configurations: (no)
• The wire protocol: (no)
• The rest endpoints: (no)
• The admin cli options: (no)
• Anything that affects deployment: (no)

Documentation

• Does this pull request introduce a new feature?
  • yes
• If yes, how is the feature documented?
  • Addition to reference-configuration.md

[merlimat]

Nice!

Additionally (in different PR) we could also allow to set custom claims on the generate token CLI tools.

[merlimat]

Merged in 2.3.1 at
9355a19