Add make commit-lint target to help contributor validate commit message locally before submitting

[sthaha]

Often PRs are blocked because the commit-lint action fails - e.g. #304 fails
because of commit-lint https://github.com/rhobs/observability-operator/actions/runs/5377063687/jobs/9760871220

It would reduce rework and toil if we provided a make target - commit-lint which allows contributors to validate commit messages locally.

It does help if all they have to run is make lint to ensure all lints are caught before submission.

[wasup-yash]

COMMIT_MSG_FILE=.git/COMMIT_EDITMSG

COMMITLINT=commitlint

lint-commit:
@echo "Running commit lint..."
@$(COMMITLINT) -e $$($(COMMIT_MSG_FILE))

we want something like this right?