Improve channel packer

[TokisanGames]

Description

Here are some features that could improve the channel packer tool:

• Display image size at bottom of each texture
• Add a convert smoothness to roughness checkbox under Roughness, which inverts it
• Above Pack button, add checkboxes for:
  • Mipmap generation (default on) - Import template: mipmaps/generate=true
    High quality (default off) - Import template: compress/high_quality=true
• Enable and fix reading DDS files
• Resize

@epitaque