Cleanup adding bot obstacles for buildings.
Half human build delay timer.
Set initial buildable health to 25%.
Remove (Advanced) Basilisk and Advanced Dretch. Add a basic implementation of Mantis.

Mantis has low health and a mediocre claw attack. It is fast and has the
ability to do quick forward pounces (copied from the Advanced Dretch).
Mantis health 50 → 75. Wallpounce cooldown 750 → 1000.
Make the Mantis slower but give its primary attack a slowing and stamina draining effect.

Mantis speed: 1.3 → 1.25, Slow time: 1s, Slow modifier: 0.75, Total stamina
lost while slowed: 20%.
Don't penalize Mantis pounce when moving up a slope.
Make AI use the Mantis pounce.
Move stamina usage, restoration and loss into a single synchronized function.
Make Mantis slow actually work.
Fix a potential loop.
Remove unused variables in ClientTimerActions.
Set both team's build delay to 60% of build time.
Merge branch 'master' into gameplay/testing

Conflicts:
	main/scripts/2d.shader
	src/gamelogic/game/g_main.c
Merge branch 'master' into gameplay/testing
Merge branch 'master' into gameplay/testing
Merge branch 'master' into gameplay/testing
Increase dretch and mantis health and regen.
Merge remote-tracking branch 'origin/master' into gameplay/testing
Merge tag 'v0.24.1' into gameplay/testing

Alpha 24, Point release 1