Backport improvements

[febus982]

• Replaces SQLite with MariaDB (tests still running on SQLite for now)
• Uses docker as default to run the infrastructure (still keeping run configurations in PyCharm for easy debugging)
• Add CORS middleware support
• Support a test di_container in FastAPI and SocketIO applications (we'll want a common DI implementation for all applications, not the FastAPI one)

[qlty-cloud-legacy]

Code Climate has analyzed commit 9cbbdaf and detected 0 issues on this pull request.

The test coverage on the diff in this pull request is 100.0% (100% is the threshold).

This pull request will bring the total coverage in the repository to 100.0% (0.0% change).

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