feat: move authentification to the django api

[jooola]

Fixes #1788
Depends on #2523

Moves the authentication mechanism to the API.

• Load the legacy login view, this sets an anonymous PHPSESSID
• Call the API /api/v2/auth/login with the PHPSESSID and a JSON body with the credentials
• The API then:
  • check the credentials as usual
  • creates a Django session
  • creates a Legacy session
    • find and reuse the anonymous PHP session data in the database
    • create a new legacy PHP session
    • regenerate the PHP session ID
    • delete the anonymous PHP session
  • returns the new PHPSESSID as cookie
• the browser is now authenticated to the API and Legacy

[jooola]

This PR is still a WIP, but I'd be happy to have feedback whether this looks like a good idea.

I didn't get answers on #1788, so I thought I implement a POC, and show how easy (understand not dirty) this could be solved.

[codecov]

Codecov Report

Attention: 35 lines in your changes are missing coverage. Please review.

Comparison is base (7db7eb0) 70.30% compared to head (fd330d7) 71.30%.
Report is 1 commits behind head on main.

❗ Current head fd330d7 differs from pull request most recent head 12660a7. Consider uploading reports for the commit 12660a7 to get more accurate results

Files	Patch %	Lines
api/libretime_api/legacy/vendor/phpserialize.py	84.93%	25 Missing ⚠️
api/libretime_api/legacy/models.py	90.00%	5 Missing ⚠️
api/libretime_api/auth/apps.py	0.00%	4 Missing ⚠️
...i/libretime_api/legacy/vendor/phpserialize_test.py	98.30%	1 Missing ⚠️

Additional details and impacted files

@@            Coverage Diff             @@
##             main    #2572      +/-   ##
==========================================
+ Coverage   70.30%   71.30%   +1.00%     
==========================================
  Files         148      153       +5     
  Lines        4024     4280     +256     
==========================================
+ Hits         2829     3052     +223     
- Misses       1195     1228      +33     

Flag	Coverage Δ
api	92.79% <88.63%> (-1.00%)	⬇️

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[paddatrapper]

This looks good to me!