Refactor weapon filenames to avoid confusions (includes models, sounds, skins, effects and shader scripts)
Closes #2787
Keep in mind, that could affect the following MRs:
IMPORTANT NOTE:
First of all, review these MRs, these should be merged after from this here due to some optimal changes.
Related maps repository MR: xonotic-maps.pk3dir!177
Edited by Dr. Jaska