Version 24: More alien themed textures

This update adds another 2 textures, mostly – but not exclusively – in the alien theme.

Updates include:

• Added metal grid variants with creeping vines.
• Added regular and weathered wood cladding, each in 4 colorways: white, yellow, blue, and red.
• Adjusted contrast of wooden fence and weathered wood textures.
• Added corrugated steel textures, in 3 variants.
• Added selection of metallic cubes/crates.