forks versus backports

[Harald Sitter]

A while ago it was pointed out to me that the forks/* git repos
includes backports. I then proposed that we don't mix forks with
backports because they are literally not the same.

So, here I go again.

New rule:

- forks/* are forks *we* maintain
- backports are to be put into a directory codifying what they were
made for e.g. backports-xenial/*

Forks include KDE software which is not maintained inside the pkg-kde
git repos (e.g. k3b) as well as software we need diverging from
compared to Ubuntu (e.g. live-build?).

Backports is everything that we do not care about sans needing a
newer/different version.

To that end if you created a repo that is in fact a backport but you
put it in the forks directory, please move it to a new
backports-xenial dir.

HS