Print messages when textures are detected as used in 3D/normal/roughness

[Calinou]

master version of #62004.

This detection automatically changes some import options, so it's important that users are aware of this.

Testing project: test_material_detect_3d.zip

Preview

Note: Normal map, ambient occlusion map and height map are all detected to be used as a roughness map, which is incorrect. The roughness map is not detected as being used as a roughness map.

res://ambientcg/Bricks079_2K_Color.jpg: Texture detected as used in 3D. Enabling mipmap generation and setting the texture compression mode to VRAM Compressed (S3TC/ETC/BPTC).
res://ambientcg/Bricks079_2K_Roughness.jpg: Texture detected as used in 3D. Enabling mipmap generation and setting the texture compression mode to VRAM Compressed (S3TC/ETC/BPTC).
res://ambientcg/Bricks079_2K_NormalGL.jpg: Texture detected as used as a normal map in 3D. Enabling red-green texture compression to reduce memory usage (blue channel is discarded).
res://ambientcg/Bricks079_2K_NormalGL.jpg: Texture detected as used as a roughness map in 3D. Enabling roughness limiter based on the detected associated normal map at res://ambientcg/Bricks079_2K_NormalGL.jpg.
res://ambientcg/Bricks079_2K_NormalGL.jpg: Texture detected as used in 3D. Enabling mipmap generation and setting the texture compression mode to VRAM Compressed (S3TC/ETC/BPTC).
res://ambientcg/Bricks079_2K_AmbientOcclusion.jpg: Texture detected as used as a roughness map in 3D. Enabling roughness limiter based on the detected associated normal map at res://ambientcg/Bricks079_2K_NormalGL.jpg.
res://ambientcg/Bricks079_2K_AmbientOcclusion.jpg: Texture detected as used in 3D. Enabling mipmap generation and setting the texture compression mode to VRAM Compressed (S3TC/ETC/BPTC).
res://ambientcg/Bricks079_2K_Displacement.jpg: Texture detected as used as a roughness map in 3D. Enabling roughness limiter based on the detected associated normal map at res://ambientcg/Bricks079_2K_NormalGL.jpg.
res://ambientcg/Bricks079_2K_Displacement.jpg: Texture detected as used in 3D. Enabling mipmap generation and setting the texture compression mode to VRAM Compressed (S3TC/ETC/BPTC).

[akien-mga]

Thanks!