Confirm which textures are affected by $basetexturetransform in PBR and update Strata docs

[vengefulcrop]

it seems that $basetexturetransform also transforms the MRAO texture

Originally posted by @TheEnderek0 in #745

There is no written official confirmation whether the above is true anywhere in the docs. Please make it clear which textures - Normal, MRAO, Emissive, Basetexture2, MRAO2 - if any, are affected by the PBR version of $basetexturetransform in addition to Basetexture and update the documentation accordingly.