Update for "Import Images as Planes" Addon.

Add more features for Material and ImageTexture settings:
1. The ability to change Interpolation Mode of the texture (linear, closest, cubic, smart).
   Before there was only linear as default.
2. The ability to change the extension parameter.
3. The ability to change a Blend Mode (Blend, Clip, Hashed).
   Before there was only Blend (or Opaque if "Use Alpha" is unchecked) as default.
4. In "Alpha Blend" case, added the "Show Backface" checkbox.
5. The ability to change the Shadow Mode (Clip, Hashed, Opaque) or disable casting shadows.
   Before there was only "Alpha Clip" as default.
6. The ability to enable Backface Culling.

Reworked:
1. Compositing Nodes, Material Settings and Texture Settings are in different layouts now.
2. "Use Alpha" checkbox has moved from "Texture Setting" to "Material Settings".

Differential Revision: https://developer.blender.org/D15744