Customize management api token provider

[tanya732]

Changes

Support for TokenProvider in Builder:

Added a new static method: newBuilder(String domain, TokenProvider tokenProvider), allowing the creation of a ManagementAPI.Builder using a TokenProvider instead of a raw API token.
Updated the Builder class to accept either an API token (wrapped in a SimpleTokenProvider) or a TokenProvider directly.
The builder now stores a TokenProvider instead of a raw API token.
The build() method now uses the provided TokenProvider directly, instead of always wrapping an API token.

API Token Handling:
The constructor Builder(String domain, String apiToken) now delegates to Builder(String domain, TokenProvider tokenProvider) by wrapping the token in a SimpleTokenProvider.

Credits

Thanks @krrrr38 for raising #729.

References

Please include relevant links supporting this change such as a:

• support ticket
• community post
• StackOverflow post
• support forum thread

Testing

Please describe how this can be tested by reviewers. Be specific about anything not tested and reasons why. If this library has unit and/or integration testing, tests should be added for new functionality and existing tests should complete without errors.

• This change adds test coverage
• This change has been tested on the latest version of the platform/language or why not

Checklist

• I have read the Auth0 general contribution guidelines
• I have read the Auth0 Code of Conduct
• All existing and new tests complete without errors