Add protobuf linter

[ClemensLinnhoff]

Reference to a related issue in the repository

#775

Add a description

• [x] Add a protobuf linter to check for style violations in PRs
• [ ] Add spell check

Take this checklist as orientation for yourself, if this PR is ready for the Change Control Board:

• [x] My suggestion follows the style and contributors guidelines.
• [x] I have taken care about the message documentation and the fields and enums documentation.
• [x] I have done the DCO signoff.
• [ ] My changes generate no errors when passing CI tests.
• [x] I have successfully implemented and tested my fix/feature locally.
• [ ] Appropriate reviewer(s) are assigned.