Add Docker image

[Neraste]

This PR adds a Dockerfile and deployment files to run the server and the front in production within a Docker image.

• Dockerfile;
• Configuration;
• Custom configuration;
• Logs format harmonisation;
• APScheduler;
• Redis;
• Environment variables prefix;
• MySQL;
  • Problem with the Player cache object that must have a migration file;
• Access logs to file;
• Run as a non-root user?
• Do not use supervisor;
• Separate configuration and configuration samples;
• Add config version check;
• Manage email by URL;
• Fix static files;
• Fix CSRF token;
• Fix static files for dev;
• Allow to use local front archive in Dockerfile.

[codecov]

Codecov Report

❌ Patch coverage is 93.10345% with 2 lines in your changes missing coverage. Please review.
✅ Project coverage is 98.52%. Comparing base (5a30ab6) to head (e14648e).

Files with missing lines	Patch %	Lines
dakara_server/playlist/signals.py	60.00%	2 Missing ⚠️

Additional details and impacted files

@@             Coverage Diff             @@
##           develop     #183      +/-   ##
===========================================
- Coverage    98.69%   98.52%   -0.18%     
===========================================
  Files           83       83              
  Lines         1994     1965      -29     
===========================================
- Hits          1968     1936      -32     
- Misses          26       29       +3     

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[Neraste]

I’m wondering if the supervisord approach is the good one, even if it’s the most advised one when you search for Docker with Django and Daphne...

[Neraste]

I eventually moved from supervisor to having several containers from the same image. It’s cleaner as it removes one level.