Shutdown all runners

[gpetretto]

Adding an option to shutdown all the runners in the projects folder.
Useful in light of backups to be performed. So also adding an option to dump the list of shutdown runners, so that they can be restarted afterward.

Posting it as draft as I would like to test it in the backup procedure before merging, but so that can already be reviewed if needed.

[codecov-commenter]

Codecov Report

❌ Patch coverage is 69.44444% with 33 lines in your changes missing coverage. Please review.
✅ Project coverage is 75.61%. Comparing base (87b533b) to head (a82dcc8).
⚠️ Report is 2 commits behind head on develop.

Files with missing lines	Patch %	Lines
src/jobflow_remote/cli/runner.py	69.44%	22 Missing and 11 partials ⚠️

Additional details and impacted files

@@             Coverage Diff             @@
##           develop     #444      +/-   ##
===========================================
- Coverage    75.63%   75.61%   -0.03%     
===========================================
  Files           51       51              
  Lines         8085     8168      +83     
  Branches      1341     1364      +23     
===========================================
+ Hits          6115     6176      +61     
- Misses        1531     1544      +13     
- Partials       439      448       +9     

Flag	Coverage Δ
all_local_tests	75.41% <69.44%> (-0.02%)	⬇️
all_tests	75.61% <69.44%> (-0.03%)	⬇️
db_tests	71.65% <69.44%> (+0.01%)	⬆️
integration_local_tests	45.51% <3.70%> (-0.47%)	⬇️
integration_remote_tests	25.79% <3.70%> (-0.22%)	⬇️
integration_tests	46.38% <3.70%> (-0.48%)	⬇️
unit_tests	26.11% <3.70%> (-0.22%)	⬇️

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Files with missing lines	Coverage Δ
src/jobflow_remote/cli/runner.py	70.62% <69.44%> (+0.17%)	⬆️

... and 1 file with indirect coverage changes

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