Support defining the texture type with a state attribute (#6240)

Fixes #6240 (closed).

This adds a state attribute that contains the texture type name and replaces named texture use (the compatibility with which is still kept so that I don't have to edit native mesh format documentation) with the use of that attribute to allow identical textures to refer to different texture types. The core issue is that named identical textures are not distinguished as attributes by the optimizer which prevents future shader visitor passes from working correctly, so the mace in the issue, being enchanted, gets borked because enchanted item glow comes with a shader visitor pass. So here's how it looks unborked and in FFP.

Another case is Better Telvanni Crystal mod, which, while it doesn't run into the issue, still gets the texture names ruined (you can see that in BetaComment output) and has its detail-mapping/glow-mapping hang by a thread.