fix housekeep.py with Python 3.14

[loqs]

What do these changes do?

Python 3.14 validates custom actions on positional arguments. Replace the argument group approach with epilog to display available commands.

Are there changes in behavior for the user?

No. housekeep.py is not packaged.

Related issue number

Fixes #594.

Checklist

• I think the code is well written
• Unit tests for the changes exist
• tox testenvs have been executed in the following environments:
  • Linux (Ubuntu 18.04, Ubuntu 20.04, Arch): qa
  • Windows (7, 10): {py36,py37,py38,py39}-{nocov,cov,diffcov}
  • WSL 1.0 (Ubuntu 18.04): {py36,py37,py38,py39}-{nocov,cov,diffcov}, pypy3-{nocov,cov}, qa, docs
  • FreeBSD (12.2, 12.1, 11.4): {py36,pypy3}-{nocov,cov,diffcov}, qa
  • Cygwin: py36-{nocov,cov,diffcov}, qa, docs
• Documentation reflects the changes
• Add a news fragment into the NEWS.rst file

[codecov]

Codecov Report

✅ All modified and coverable lines are covered by tests.
✅ Project coverage is 97.84%. Comparing base (dc78ef6) to head (4f04cf6).

Additional details and impacted files

@@            Coverage Diff             @@
##           master     #595      +/-   ##
==========================================
+ Coverage   97.75%   97.84%   +0.08%     
==========================================
  Files          23       23              
  Lines        5709     5709              
  Branches      351      351              
==========================================
+ Hits         5581     5586       +5     
+ Misses         79       73       -6     
- Partials       49       50       +1     

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