technic_chests was depending on the technic mod, for the top-level
"technic" table and the technic.swap_node function. Resolve that by
sharing the top-level table and inlining the one use of the function.
It was also depending on technic_worldgen, for the definitions of
cast iron and wrought iron. Make the use of cast iron conditional on
technic_worldgen, falling back to default "steel". Change the use of
wrought iron to directly use default "steel", to which it is aliased
anyway.
Override the default mod's iron/steel substance, replacing it with three
metals: wrought iron (pure iron), carbon steel (iron alloyed with a little
carbon), and cast iron (iron alloyed with lots of carbon). Wrought iron
is easiest to refine, then cast iron, and carbon steel the most difficult,
matching the historical progression. Recipes that used default steel are
changed to use one of the three, the choice of alloy for each application
being both somewhat realistic and also matching up with game progression.
The default:steel{_ingot,block} items are identified specifically with
wrought iron. This makes the default refining recipes work appropriately.
Iron-using recipes defined outside technic are thus necessarily
reinterpreted to use wrought iron, which is mostly appropriate.
Some objects are renamed accordingly.
Rather than use the default steel textures for wrought iron, with technic
providing textures for the other two, technic now provides textures for
all three metals. This avoids problems that would occur with texture
packs that provide default_steel_{ingot,block} textures that are not
intended to support this wrought-iron/carbon-steel/cast-iron distinction.
A texture pack can provide a distinct set of three textures specifically
for the situation where this distinction is required.
Incidentally make grinding and alloy cooking recipes work correctly when
ingredients are specified by alias.
