In-game shadow settings

We had those over a decade ago! We can get them back.

screenshot010

0.35.0

screenshot440

!5442 (merged)

изображение

(launcher, current)

Notes for further polishing (mostly for myself):

The implementation in !5442 (merged) doesn't fully replace the launcher implementation at the moment but ideally we'd just keep the in-game one and extend it to support things the launcher didn't, like number of shadow maps.

As you can see, the one thing that would still need to be added after !5442 (merged) is merged to fully deprecate the launcher implementation is plane computation method (fade start is whatever, we dropped that for lights too). Probably not too difficult.

Enable Shadows checkbox should probably also return for the convenience of turning shadows on/off at once, which would require changing the defaults for individual checkboxes to be on and blocking individual checkboxes when it's off. The bonus is that it will explain clearly that shadows carry their own performance hit just from being enabled. Note !5442 (merged) originally had this checkbox along with the necessary translations.