add subcommand for updating mirror detail

[elfkuzco]

Changes

• add subcommand for updating a mirror's details

  • update the list of other countries for a mirror using --regions. This sets the other_countries using all the countries found in the provided regions in addition to the countries in the default region of the mirror.
  • update the default region for a mirror using --region
  • update the default country of a mirror using --country

  These changes (in additon to #42 ) lay the foundation for #39 as the initial db schema didn't have regions or country information in mirrors

[codecov-commenter]

Codecov Report

Attention: Patch coverage is 28.76712% with 52 lines in your changes missing coverage. Please review.

Project coverage is 69.66%. Comparing base (656e88d) to head (ae7183c).

Files	Patch %	Lines
backend/src/mirrors_qa_backend/entrypoint.py	0.00%	33 Missing :warning:
backend/src/mirrors_qa_backend/cli/mirrors.py	0.00%	13 Missing :warning:
backend/src/mirrors_qa_backend/db/mirrors.py	77.77%	4 Missing and 2 partials :warning:

Additional details and impacted files

```diff @@ Coverage Diff @@ ## main #43 +/- ## ========================================== - Coverage 72.75% 69.66% -3.10% ========================================== Files 30 30 Lines 881 946 +65 Branches 81 93 +12 ========================================== + Hits 641 659 +18 - Misses 222 267 +45 - Partials 18 20 +2 ```

:umbrella: View full report in Codecov by Sentry.
:loudspeaker: Have feedback on the report? Share it here.