ui: datastore permissions: allow ACL path edit & query namespaces

Without namespaces this had not much use, but now that we can have
permissions below we should allow so.

For convenience also query the namsepaces here and add them to the
list of available ACL paths, the read-dir shouldn't be that expensive
(albeit, we could cache them in the frontend)

Signed-off-by: Thomas Lamprecht <t.lamprecht@proxmox.com>

www/datastore/Panel.js

@@ -97,6 +97,7 @@ Ext.define('PBS.DataStorePanel', {
 	    iconCls: 'fa fa-unlock',
 	    cbind: {
 		aclPath: '{aclPath}',
+		datastore: '{datastore}',
 	    },
 	},
     ],