doap category infrastructure
deploy: Propertly append multiple kernel arguments with --karg-proc-cmdline

We want to allow multiply specified arguments, as it's useful for
things like console= and rd.lvm.lv.

See: https://bugzilla.gnome.org/show_bug.cgi?id=721136

Reported-by: Dusty Mabe <dustymabe@gmail.com>
packaging: Make the ostree rpm own and create /etc/ostree/remotes.d/
pull: Add --old argument, as a simpler way to get older commits

This allows clients to easily get older commits, to deploy an older
known good commit after it isn't the latest or to get older commits for
bisecting problems once found.
cherry-pick: Add cherry-pick command, as a simpler commit --tree=ref=...

Add a cherry-pick command, as git does. This mostly works the same way
as --tree=ref= to commit, but if you don't override the subject and
message it'll reuse the values from the original commit.
cherry-pick: Add documentation for cherry-pick command