to use on_rightclick instead, for consistency with other parts of minetest,
minetest_game, etc.

see https://github.com/t4im/profiler/#labeling

to bring them all together into one "category" instead of being scattered across the directory
also combine a couple dupes.

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

Telephone : nodeboxes cleaning.

package the two together as a modpack so that regular homedecor users don't
see a functional change, but others can take signs_lib and use it as a
standalone mod.

also get rid of some *~ files

Just a minimal code reduction, but big reduction in code
duplication. This could help if in the future, support for
different "internationalization" mods will be added, or in
case Minetest supports I18N/L10N internally in the engine.

(underscore -> period).  Similarly for intllib calls and the DEBUG variable.

Also fixed a screwed up register_craftitem that was overriding a register_node
call for the same object (wooden table legs).  Got rid of the old "mkII" wooden
table legs.