[ETF] Entity Texture Features

[6.1.3]

• added additional null checks to fix some odd mod crashes
• fixed the config breaking with some mods
• fixed player skin tool pixel select image being sideways in 1.21

• fixed painting variant rendering in 1.21
• made it so the "aztec" painting only variates with a .properties file because of "aztec2" existing in vanilla

fix for sodium 0.5.9, retains compat with earlier sodium