app-emulation/lxc: Bump to v3.0.0

app-emulation/lxc: Bump to v3.0.0

Many notable changes:

1. Drop python and lua. Bindings are no longer bundled with LXC and live
in separate packages.

2. Drop cgmanager USE flag. cgmanager isn't supported anymore by
upstream.

3. Remove versionator inherit. It wasn't used.

4. Remove two patches which were simple cherry pick from upstreams.
They're applied upstream now.

5. Remove notice about path change in v1.1. It's been a while, it lost
relevance.

6. Remove start-ephemeral bash completion. Upstream finally removed it
from its own completions.

7. Add "pam" USE flag for the compilation and installation of the new
builtin "pam_cgfs.so" module.

Closes: https://bugs.gentoo.org/652582
Closes: https://github.com/gentoo/gentoo/pull/7934

Package-Manager: Portage-2.3.24, Repoman-2.3.6
Signed-off-by: Matthias Maier <tamiko@gentoo.org>