[manila] add metrics for limes capacity plugin

we move the function definition away from limes and take
ownership in manila

additionally we allow 'hxm_backups' snapshot policy and
use the new harvester metrics

openstack/manila/aggregates/storage/limes.rules

@@ -0,0 +1,27 @@
+groups:
+  - name: manila-limes
+    rules:
+      # building a heuristic to tell how much space is consumed by backend (non-manila) snapmirror replication.
+      # we look at the source (volume_type is not dp)
+      # we only look at volumes that have dedicated snapshot policy: case insensitive hxm_backups or ec2_backups
+      # we require share type and project id to be able to associate to valid billing targets.
+      - record: netapp_snapmirror_total_bytes
+        expr: |
+            netapp_volume_total_bytes:pre * on (app, host, svm, volume)
+                group_left(snapshot_policy, state) netapp_volume_labels{
+                    project_id!="",
+                    share_type!="",
+                    snapshot_policy=~"(?i:(hxm|ec2))_(?i:(backups))",
+                    state="online",
+                    volume_type!="dp"}
+
+      - record: netapp_snapmirror_used_bytes
+        expr: |
+            netapp_volume_used_bytes:pre * on (app, host, svm, volume)
+                group_left(snapshot_policy, state) netapp_volume_labels{
+                    project_id!="",
+                    share_type!="",
+                    snapshot_policy=~"(?i:(hxm|ec2))_(?i:(backups))",
+                    state="online",
+                    volume_type!="dp"}
+