Allow the `unorphan` action to be used to `give` a package to someone else

This brings back the behavior of pkgdb-cli 1.+ and correspond to what the
documentation says.

Fixes https://fedorahosted.org/pkgdb2/ticket/23
Add the `give` action to pkgdb-cli

This allows an user to give his/her package or an pkgdb admin to give an
orphaned package to someone else