mgr/cephadm: store device info separately from rest of host cache

mgr/cephadm: store device info separately from rest of host cache

device info tends to take up the most space out of
everything, so the hope is by giving it its own
location in the config key store we can avoid hitting
issues where the host cache value we attempt to
place in the config key store exceeds the size limit

Fixes: https://tracker.ceph.com/issues/54251
Fixes: https://tracker.ceph.com/issues/53624
Signed-off-by: Adam King <adking@redhat.com>