vt(4) uses hardcoded values for standard 16-colors VGA palette
and the only way to modify it at the monent is by patching kernel.
This patch introduces set of loader variables that can be set
to alter pallete values. Variable name pattern is kern.vt.color.N.rgb
where N is a pallete index varying from 0 to 15. The value is
either coma-separated rgb triplet with values in a range of 0 to 255,
i.e. "255,255,255". Or HTML-like hex-triple, i.e: "#ffffff".
These values can be configured in loader.conf(5)