fix(icons): themed icons for custom images

[secp192k1]

what

Custom icons don't work when using the material you "Minimal" icon scheme, the image doesn't show in Pixel Launcher

Minimal Theme Disabled	Minimal Theme Enabled

whats new

So just grab the original picture and apply some math to get the alpha values and create a monochrome mask of the custom image rather than always using the aliucord monochrome icon

New Minimal Theme Disabled	New Minimal Theme Enabled

manager option

added multiple methods of color masking, since some pictures look better with a different color scheme

massive screenshot preview from manager

[rushiiMachine]

I don't see a reason to provide multiple different monochrome themed icon styles, they all look the exact same.
You could just pick the one that looks best in most cases and just make that the only option.
Inverted is even more pointless

[secp192k1]

@rushiiMachine My example image wasn't the best... I will attach a better one in this comment, I'll follow through with that suggestion and just keep the Standard color scheme just in case