ARCHBOM-1357: add catch-all to CodeOwnerMetricMiddleware

[robrap]

Description:

Added a catch-all capability to CodeOwnerMetricMiddleware when CODE_OWNER_MAPPINGS includes a '*' as a team's module. The catch-all is used only if there is no other match.

JIRA:

ARCHBOM-1357

Reviewers:

• [x] @edx/arch-review (Required)

Merge checklist:

• [x] All reviewers approved
• [x] CI build is green
• [X] Version bumped
• [X] Changelog record added
• [X] Documentation updated (not only docstrings)
• [x] Commits are squashed

Post merge:

• [ ] Create a tag
• [ ] Check new version is pushed to PyPi after tag-triggered build is finished.
• [ ] Delete working branch (if not needed anymore)