Merge tag 'v0.25.0' into gameplay/viech

Alpha 25
Allow jetpack to activate when falling down after a jump.
Remove battery pack. Make radar a backpack and make it use the battery pack's placeholder model.
Change magazine sizes to compensate for battery pack removal.
Change Lightgrid interpolation to match q3 more.

The directed light intensity is interpolated now without consideration of its
direction. That may be physically less plausible, but otherwise directed
lighting can get turned down too much.
Fix lightvector scaling.
Fill in lightgrid samples in walls with interpolated values.

The 3d texture cannot skip samples in walls, so to avoid darkening
of entities near walls and floors there should be light samples inside
walls.
Fix a typo inside ReadLightGrid. This fixes the flickering effect experienced on nvidia hardware.
Normalize r_ambientScale and r_normalScale, remove the CVAR_CHEAT flag of the latter.
Reduce health for dretch (35 → 30) and mantis (80 → 75), increase mantis pounce cooldown.
Remove armageddon vote.
Make turret prefer follow-up target that it can aim at more quickly.
Change a few default cvar values in the gamelogic.
Simplify structure deconstruction and clean up some related code.

This removes the g_markDeconstruct option.
Make the booster eject spores when healing an alien.
Don't use FLT_MAX inside the gamelogic.
Display total (used + spare) power and the threshold in buildable status displays.
Make the telenode require no power since it doesn't unpower anyway. Tweak power supply values to compensate.
Flip the turret initial aim direction when facing a buildable.
Cleanup cvar definitions in g_main.c.