main/util-linux: finish the package splitting and clean up depends list

In !20659 (merged), I said:

I think that util-linux should act as a metapackage, and the commonly-used utils should be split out into individual subpackages, with the rest going into util-linux-misc.

On top of that, _mv_bin() should generate an install_if="util-linux" rule for the subpackages, and the depends list should be removed.

Whoever wants to work on that should feel free. I suggest waiting until after 3.14 release and merging this in the interim.

Implement this in 3.15.