ui: ceph: add more compatibilty code for versions

ui: ceph: add more compatibilty code for versions

we now have to handle the version of 'old' nodes, as well as the
new nodes, which are missing the 'version' field in the metadata/osd call

so set the 'versions' object to a default empty object for osds
and get the host version directly from the treenode
(the parent node of the osd node)

also compare the host version in the dashboard by getting first the
new version field, and the old one as fallback.

Signed-off-by: Dominik Csapak <d.csapak@proxmox.com>