Hotchpotch

Implement kinder creepers, the hotchpotch:creeper_explosion_delay gamerule can control how long in ticks it takes for a creeper to explode, by default this is the same as vanilla (30 ticks, 1.5 seconds)

Whilst this feature is dubbed kinder creepers, you can make the more punishing down to 1/20th of a second to explode.

• Added Deepslate stairs, slabs, and walls.
• Removed some WIP content until it has been finished.

Port to 26.1, probably some other changes I forgot about.

Initial release for 26.1-snapshot.1