[ci] enhance code quality checks

[timothytrippel]

Currently, the code quality checks run in CI on this repo consists of:

1. a license header check
2. gofmt check
3. clang-format check

We should enhance these to also add other checks done in the opentitan repo:

• buildifier check (for Bazel BUILD file autoformatting)
• protolint for linting/formatting protos
• whitespace check
• commit formatting
• include guard lint check
• exec bit check
• bazel banned rules check