Splitting (Muon) Discover from muon repository

[Aleix Pol]

Hi,
One of the things discussed in the Muon bof was the possibility to get
muon (as in the muon package manager) in a separate repository than
Muon Discover/Updater.

The background is that muon-packagemanager is using a different
technology than the rest and the target audience is probably quite
different, so it doesn't really make much sense to keep them together.
Additionally we're struggling to find maintainers for the
muon-ṕackagemanager and I'd hope it would be easier to adopt it if
it's alone, rather than with another slightly related project.

Anyway, I'd like to leave 2 repositories:
- muon, that will have muon-packagemanager
- discover, that will have discover and updater. I'd also like to drop
the Muon part from Discover eventually as well and leave Discover as
is.

Also I can work on it during this week, I'd like to make sure it won't
have a bad impact on the next Plasma release though. If that was the
case, I can wait.

Thoughts?
Aleix