Neaten folder structure, improve docs slightly

The services/*/ names are kind of arbitrary, but should be a bit easier to
comprehend than one massive list.

I'll push this commit somewhere public after I've verified I can actually reboot
and not brick anything.
Add supervise/ dirs to gitignore
Fix defaults in mingetty/kmscon

They didn't actually work without the suffix. Now they do (and run on different
terminals by default).
Import agetty script from my ebuild repo

Might as well have them all in one place. Also allows people to use the working
version without necessarily installing my version of runit*.ebuild.
Add a workaround to named/run script