Support of Protobuf schemas

[raminqaf]

Currently, the streams explorer is not supporting topics with Protobuf schemas and fails to load the schema when displaying the topic details.

[disrupted]

We currently support only Avro schemas and retrieve them from a Schema Registry or Karapace server, inside the SchemaRegistry class. Recent versions of both Schema Registry and Karapace added support for Protobuf and JSON schemas. Therefore adding support for Protobuf would be a great enhancement.