Furnace assets

[careeoki]

Following suggestions in #1151, this adds the nonfunctional kiln, furnace, bellows, and chimney blocks.

And I even did lit textures.

This is what I imagine for recipes:

Kiln
- 8 any stone

Furnace
- 8 terracotta

Bellows
- 2 planks
- 2 copper
- 4 leather

Chimney
- 4 terracotta
- 2 iron

There is a lot of changes because I had to do some consistency fixes along the way:

• terracotta grout colour
• copper block palette changes
• change 1 colour of the torch flame

[ikabod-kee]

Good work on the textures!!

[Argmaster]

Changes in copper were not advertised, what's up with this?

[careeoki]

I did, at the bottom of my post.
I tweaked the palette so it would suck less/work better alongside other colours (for bellows)
You can hardly notice the difference ingame. It's primarily a consistency change.

[Argmaster]

Oh sorry

[Argmaster]

I find this very worthy of merging.