postinstall: Copy ceph ansible modules if present
ceph-ansible 3.1 (and newer) refactored the handling of ceph keys
by leveraging a new `ceph-key` ansible module.
To support the new ceph-ansible 3.1, we copy any ceph ansible modules
similar to the way we currently handle ceph roles.
This change is backwards compatible with the current ceph-ansible 3.0.
Signed-off-by: Alexandru Antone <Alexandru.Antone@enea.com>
Signed-off-by: Alexandru Avadanii <Alexandru.Avadanii@enea.com>
Change-Id: I41364261dd8f445ddedf9d07eaa2cadc9da90b5e