Add nether

[FloofCat]

Draft PR. Refer to #39.

Some questions I have about implementation is:

• Nether reactors usually look like this: https://www.youtube.com/watch?v=vDHuO-OAlf8. Do we want an exact implementation of this PE version?
• If we are deviating from the PE version, do we have any specifics we want? The ideas I had for now is - convert grass / mud [or surface blocks] to netherrack, water to lava, tree logs to nether wood [color undecided]. Maybe some chances to get gold ore and quartz ore here too.
• Is there a crafting recipe we want for the reactor? What mobs do we want? My implementation plans to have zombie piglins, blazes (low chances - if our goal is to at some point have an end dimension or some form of that) & piglins.

cc: @p2r3

[coder123q]

is this still going to get added?

[FloofCat]

I plan to complete this in a few days.

I've been busy with some irl stuff - apologies.

[p2r3]

To answer your questions - what I had in mind was a much simpler structure with an inexpensive check. It's hard to come up with something thematically relevant on the spot, but an example would be the action of replacing a lava source with a block of redstone. Unlikely to happen in regular gameplay, and is relatively cheap to check for.

Instead of generating a box around the player, I was thinking it could perhaps convert nearby "natural" blocks (e.g. stone, dirt, grass) within some radius to Netherrack and other Nether blocks. A few relevant mobs would spawn near the source block, and that'd be the end of it. Just a one-time event, no repeat spawning or random treasure items.