[REQ] Allow importing of BC7 .dds textures

[monkeyman192]

Is your feature request related to a problem? Please describe.
Importing scenes such as MODELS\COMMON\CHARACTERS\BACKPACK.SCENE.MBIN has issues as some of the textures as BC7 dds files which blender sadly doesn't seem to be able to support.

Describe the solution you'd like
This tool https://github.com/microsoft/DirectXTex seems to be able to handle and convert them just fine. Maybe we can use this to convert any unsupported textures on the fly and then load them instead

While we are at it, maybe we can use the program to extract images which are multiple layers so we can use the multiple layers as HG does in textures.