add schema registry support for protobuf

[bananaaggle]

Confluent's Schema Registry supports for deserializing protobuf now. So I add this feature to druid-protobuf-extension module. This module only work when user provide a .desc file in old version. Now it can get schema from schema registry dynamically.
This submission adds the io.confluent:kafka-protobuf-serializer:6.0.1 dependency to the druid-protobuf-extension module.
Old spec is:

"parser": {
      "type": "protobuf",
      "descriptor": "file:///tmp/metrics.desc",
      "protoMessageType": "Metrics"
      ......
}

New spec is:

"parser": {
      "type": "protobuf",
      "protoBytesDecoder": {
           "type": "schema_registry",
          "url": "http://XXXXXX:8081",
          "capacity": 10,
        }
      ......
}

and

"parser": {
      "type": "protobuf",
      "protoBytesDecoder": {
          "type": "file",
          "descriptor": "file:///tmp/metrics.desc",
          "protoMessageType": "Metrics"
        }
      ......
}

Description

Fixed the bug ...

Renamed the class ...

Added a forbidden-apis entry ...

---

This PR has:

• been self-reviewed.
  • using the concurrency checklist (Remove this item if the PR doesn't have any relation to concurrency.)
• added documentation for new or modified features or behaviors.
• added Javadocs for most classes and all non-trivial methods. Linked related entities via Javadoc links.
• added or updated version, license, or notice information in licenses.yaml
• added comments explaining the "why" and the intent of the code wherever would not be obvious for an unfamiliar reader.
• added unit tests or modified existing tests to cover new code paths, ensuring the threshold for code coverage is met.
• added integration tests.
• been tested in a test Druid cluster.

---

Key changed/added classes in this PR

• MyFoo
• OurBar
• TheirBaz

[bananaaggle]

MVN package failed caused by lack of io.confluent:kafka-protobuf-serializer:6.0.1. Is Druid CI use a independency MVN repo instead of public MVN repo? I see same problem in this pull request:#3529. Can I add a new dependency for this extension? And is there someone can help me?