www-client/luakit: update live ebuild

www-client/luakit: update live ebuild

Add prefix to emake so luakit can find modules and fix various repoman
warnings.

  - Bump copyright
  - Bump to EAPI 7
  - Inherit xdg-utils
  - Use https for repo uri
  - Add PREFIX to emake in compile phase
  - Edit Makefile to install uncompressed man page
  - Add xdg functions for desktop file

Closes: https://bugs.gentoo.org/715184
Package-Manager: Portage-2.3.96, Repoman-2.3.22
Signed-off-by: Kristopher Keller <kristopher004@gmail.com>
Closes: https://github.com/gentoo/gentoo/pull/15157
Signed-off-by: Joonas Niilola <juippis@gentoo.org>