Trims off effect layers, makes rendering a bit more sane

[LemonInTheDark]

Description

The existing multiplier is lower then layer values encouraged by byond when combined with layering defines, so it breaks easy. I'm removing effect layers which should make the value at least a little more sane (though at a max of 4999 there is still risk of intermixing, should we be using float64 or someodd?)

I was not able to get the build process to work, so this is unfortunately untested. Apologies. Should close #292

Type of change

• Minor changes or tweaks (quality of life stuff)
• Bug fix (non-breaking change which fixes an issue)
• New feature (non-breaking change which adds functionality)
• Breaking change (fix or feature that would cause existing functionality to not work as expected)
• This change requires a documentation update

[LemonInTheDark]

I had to bump the multiplier up significantly, I am like 90% sure this is starting to edge on floating point rounding errors.
Why do we multiply layer by 1000? is it to handle tiny baby values? could the final layer be a float 64 or would that break something? (Would it be worth removing applied effect layers (TOPDOWN_LAYER, EFFECT_LAYER, BACKGROUND_LAYER) as well as doing this to reduce the final value?)

Please advise

NVM I'm doing it

Done

[SpaiR]

@LemonInTheDark I've fixed the pipeline. Please update the PR to the latest main to proceed with CI