League System UI ready for testing

The UI for the division system has been merged into the client code and is available for testing in the alpha release of the client. https://github.com/FAForever/downlords-faf-client/releases/tag/v2021.12.0-alpha-2
Additional changes on the release can be found at https://forum.faforever.com/topic/3024/client-2021-12-0-upcoming-features
The data you can see when you open the leaderboards is from a test season that happened under the radar. I did this to make sure the backend is working and to get some data to be able to properly test the UI. In the meantime I tuned the values how people get placed in the divisions, so don't expect to be in the same division again, if you find your entry in the leaderboards. Your division will now also be displayed in the matchmaker tab instead of the "In placement" text.
The beginning of the first official season will wipe the test data and also bring support for the 4v4 queues. Please report any bugs you can find.