Add jitter to collision stun

[Dr-Horv]

Problem: Two bots may end up indefinitely stunning each other by headbutting for the same tile over and over again

Proposed solution: Add randomness to the stun duration for collisions which would allow one bot to escape an aggressor.

• Add setting for minimum stun duration
• Add setting for maximum stun duration
• Change collision stuns to be random between min and max