cephadm: convert get_container_mounts to use a DaemonIdentity argument

cephadm: convert get_container_mounts to use a DaemonIdentity argument

Convert get_container_mounts to use a DaemonIdentity argument, and in
order to do so: split get_container_mounts_for_type out of
get_container_mounts. get_container_mounts will take a DaemonIdentity
and safely assume that the fsid, daemon_type, daemon_id triple is
available whereas get_container_mounts_for_type has the functionality
of only requiring the fsid and daemon_type.

Signed-off-by: John Mulligan <jmulligan@redhat.com>