AntiCreeper

- added mode system

- change mode in the config function

Modes:
1: Traditional; sets explosion radius to 0.
2: Experimental; uses mobGriefing gamerule to ensure creepers still do damage to entities but isn't reliable. This only disables mob griefing temporarily!
3: Ignition; ignites every creeper in range (3 blocks) but creepers are forced to explode this way. Works flawless.