This branch...
Makes a new filetype for Krita palettes: KPL.
These palettes can have groups, and unlike GPL palettes, they can save high bit depth colors. Then, we have the necessary functions to deal with adding/removing/searching for colorsetentries inside groups.
Thanks to @lsegovia we also have SBZ(swatchbooker) support.
I was not able to add embedded palette support. I came across a bug that I couldn't resolve, as noted in T5282.
This fixes T4121