Update built in SDL version for windows

[ensiform]

to 2.30.6

Make r_sdlDriver settable at startup to choose which SDL backend is used "wayland" for example.

Add r_allowScreensaver cvar to allow enabling screen to sleep while game is running.

Turn on hint to bring back pre-SDL 2.0.14 behavior for alt-tab on focus loss.

Add s_sdlDriver to choose which backend is used for SDL audio ("pulseaudio" or "pipewire" for example)

Silence Apple OpenGL deprecated warnings

[JKSunny]

Fwiw, can confirm this working for my EternalJK master fork with Vulkan. Also tested alt-tabbing and r_allowScreensaver 1, didnt test s_sdlDriver On windows 10