Feat: use workers even without Redis

[Marc-Andrieu]

Description

Summary

Now we can enjoy using workers locally even without Redis: it was only useful to set a lock on initialization.

Changes Made

• made a distinction between the number of workers, and having a Redis instance or not
• the fallback Redis-less lock is just allowing the first worker to run the 5 init functions: the iterator of workers always output the element in the same order (tested locally in dev (necessarily 1 worker), and in run with 1 (no --worker flag), 2, 3, 4, 6, 8 and 12 workers)

Type of Change

• 🐛 Bug fix (non-breaking change which fixes an issue)
• ✨ New feature (non-breaking change which adds functionality)
• 🔨 Refactor (non-breaking change that neither fixes a bug nor adds a feature)
• 🔧 Infra CI/CD (changes to configs of workflows)
• 💥 BREAKING CHANGE (fix or feature that require a new minimal version of the front-end)

Impact & Scope

• Core functionality changes
• Single module changes
• Multiple modules changes
• Database migrations required
• Other

Testing

• Added/modified tests that pass the CI
• Tested in a pre-prod
• Tested this locally

Documentation

• Updated docs accordingly (docs.myecl.fr) :
• Code includes docstrings
• Inline comment
• No documentation needed

Checklist

• My code follows the style guidelines of this project
• I have commented my code, particularly in hard-to-understand areas
• Any dependent changes have been merged and published (Indicate the linked PR for the dependent changes)

Additional Notes

Add any other context, screenshots, or information about the pull request here.

[codecov]

Codecov Report

❌ Patch coverage is 37.50000% with 5 lines in your changes missing coverage. Please review.
✅ Project coverage is 85.66%. Comparing base (513a563) to head (cb0acd0).

Files with missing lines	Patch %	Lines
app/utils/initialization.py	40.00%	3 Missing ⚠️
app/app.py	33.33%	2 Missing ⚠️

Additional details and impacted files

@@            Coverage Diff             @@
##             main     #874      +/-   ##
==========================================
- Coverage   85.67%   85.66%   -0.02%     
==========================================
  Files         189      189              
  Lines       14572    14570       -2     
==========================================
- Hits        12485    12481       -4     
- Misses       2087     2089       +2     

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