Lua way to toggle r_shadowfromanyworldlight for servers

[Akabenko]

I’ve seen reports that the dynamic light system doesn’t work without r_shadowfromanyworldlight enabled, so I support the idea of adding a way to toggle it serverside.

#1458

[robotboy655]

Duplicate of #1458

[robotboy655]

I have looked into this, and there was a bug with vrad.exe that made the option "Cast entity shadows" to not work in-game. This bug is fixed on x86-64 beta, so if you (re)compile your map on that beta, the feature will work as expected on all versions of the game.

Other versions of the game will also get the map compiler fix, but later.

I have also added extra info to that keyvalue on light entity about how to make it work properly.