Remove the protos and generated codes inside this project.

[archerny]

Description

The proto files and generated code should be managed in a single repo, rather than scatter them everywhere. It will be more maintainable that other projects depend on one single proto repo.

Proposal

Since ceresdb-client-java is a pure Java written project, we can add ceresdb-proto-internal as a dependency to the pom. And then remove the protos and related codes maintained inside this project.

Additional context

no