[improve][io] Support Protobuf schema for Kafka source connector

[jiangpengcheng]

Motivation

The Kafka source connector support schema registered in schema registry, but it only support Avro for now, while the schema registry also supports Protobuf, it's better to support it too

Modifications

Update the Kafka source connector to make it support Protobuf schema

Verifying this change

• Make sure that the change passes the CI checks.

• This change added tests and can be verified as follows:

  • Added integration tests for using KafkaProtobufDeserializer to create Kafka source connector

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

If the box was checked, please highlight the changes

• Dependencies (add or upgrade a dependency)
• The public API
• The schema
• The default values of configurations
• The threading model
• The binary protocol
• The REST endpoints
• The admin CLI options
• The metrics
• Anything that affects deployment

Documentation

• doc
• doc-required
• doc-not-needed
• doc-complete

Matching PR in forked repository

PR in forked repository: jiangpengcheng#39