DAOS-18793 cq: Add mapping for cmocka -> ftest tags

[daltonbohning]

• Map cmocka test files to corresponding ftest tags so the tests are automatically ran by default.
• Skip unit tests for cmocka-only changes.
• refactor gen_commit_pragma stop_on_match handling Handle stop_on_match at the path-level in addition to individual pragma-level.

Doc-only: true

Steps for the author:

• Commit message follows the guidelines.
• Appropriate Features or Test-tag pragmas were used.
• Appropriate Functional Test Stages were run.
• At least two positive code reviews including at least one code owner from each category referenced in the PR.
• Testing is complete. If necessary, forced-landing label added and a reason added in a comment.

After all prior steps are complete:

• Gatekeeper requested (daos-gatekeeper added as a reviewer).

[github-actions]

Ticket title is 'ftest: add mapping for cmocka tests to ftest tags'
Status is 'In Progress'
https://daosio.atlassian.net/browse/DAOS-18793