chore: Migrate to use proto files from common proto repo for all Waku protocols

[chaitanyaprem]

Background

As of now, Waku protocol proto files are duplicated in go-waku repo from https://github.com/waku-org/waku-proto and then the code is generated from them to use. This causes trouble because we need to keep track of reference proto file and its changes and manually diff and apply changes when a new version is created.
This process would be errorprone.
Instead, once proto files are migrated to waku-org repo, generate all protobuf code from those proto files by making that repo a sub-module of go-waku repo.

Details

Note: Original proto files may have different package convention than what is used in go-waku, hence protogen command takes a flag which can specify the package to be used for the generated code.

Acceptance criteria

Need to make sure all unit tests pass.
Ensure interop tests with nwaku also pass.