also avoid facedir setting for plantlike, raillike and firelike to avoid clashes if paramtype is used internally in the engine for something else

better UV mapping on light bulb

also documented the meanings of the different lines.

... also remove useless definitions (set by default).

this undocumented function is internally being used for falling or attached nodes and shouldn't be needed here

use new API function to handle the second-node air

move most other homedecor nodes to the new registration function, remove any unnecessary fields due to minetest or homedecor defaults