cardano-rpc | Use buf for code generation instead of cabal/protoc integration

[carbolymer]

Changelog

- description: |
    <insert-changelog-description-here>
# uncomment types applicable to the change:
  type:
  # - feature        # introduces a new feature
  # - breaking       # the API has changed in a breaking way
  # - compatible     # the API has changed but is non-breaking
  # - optimisation   # measurable performance improvements
  # - refactoring    # QoL changes
  # - bugfix         # fixes a defect
  # - test           # fixes/modifies tests
  # - maintenance    # not directly related to the code
  # - release        # related to a new release preparation
  # - documentation  # change in code docs, haddocks...
# uncomment at least one main project this PR is associated with
  projects:
  # - cardano-api
  # - cardano-api-gen
  # - cardano-rpc
  # - cardano-wasm

Context

Additional context for the PR goes here. If the PR fixes a particular issue please provide a link to the issue.

How to trust this PR

Highlight important bits of the PR that will make the review faster. If there are commands the reviewer can run to observe the new behavior, describe them.

Checklist

• Commit sequence broadly makes sense and commits have useful messages
• New tests are added if needed and existing tests are updated. See Running tests for more details
• Self-reviewed the diff

[github-advanced-security]

hlint found more than 20 potential problems in the proposed changes. Check the Files changed tab for more details.