As a potential toolchain improvement for Funtoo, add a nice new autogen for the mold linker in core-kit next sys-devel package category.

This will allow folks to use mold as a drop in replacement to GNU binutils ld if they so desire (this is opt-in only and hard masked)

Upstream source code is here: https://github.com/rui314/mold

Gentoo Wiki Reference is here: https://wiki.gentoo.org/wiki/Mold

Gentoo Ebuild is here for Funtooification: https://packages.gentoo.org/packages/sys-devel/mold