Registration API, remove unused static webpage, ...

[JOKITON]

• Handle from Proxy container configuration (nginx.conf) relative URLS (/api) to make use of API calls into App container (Backend).
• Delete (static/) and change App container configuration (urls.py, views.py, ...) to be able to handle API Registration calls correctly and save them in DB container.
• Add dependencies to App container to handle web API calls and requests from different origins ( CORS ).
• Remove dependencies for Gunicorn from App container, since Backend is no longer used for serving static webpage files.
• Remove all traces of configuration for the HTTP server.
• ...

[JOKITON]

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