Alerting: Support for simplified notification settings in rule API (#81011)

* Add notification settings to storage\domain and API models. Settings are a slice to workaround XORM mapping
* Support validation of notification settings when rules are updated

* Implement route generator for Alertmanager configuration. That fetches all notification settings.
* Update multi-tenant Alertmanager to run the generator before applying the configuration.

* Add notification settings labels to state calculation
* update the Multi-tenant Alertmanager to provide validation for notification settings

* update GET API so only admins can see auto-gen

pkg/services/ngalert/api/test-data/post-rulegroup-101-export.hcl

@@ -77,5 +77,14 @@ resource "grafana_rule_group" "rule_group_0000" {
     no_data_state  = "NoData"
     exec_err_state = "Alerting"
     is_paused      = false
+
+    notification_settings {
+      receiver            = "Test-Receiver"
+      group_by            = ["alertname", "grafana_folder", "test"]
+      group_wait          = "1s"
+      group_interval      = "5s"
+      repeat_interval     = "5m"
+      mute_time_intervals = ["test-mute"]
+    }
   }
 }

pkg/services/ngalert/api/test-data/post-rulegroup-101-export.json

@@ -109,7 +109,15 @@
           "noDataState": "NoData",
           "execErrState": "Alerting",
           "for": "0s",
-          "isPaused": false
+          "isPaused": false,
+          "notification_settings":{
+            "receiver":"Test-Receiver",
+            "group_by":["alertname","grafana_folder","test"],
+            "group_wait":"1s",
+            "group_interval":"5s",
+            "repeat_interval":"5m",
+            "mute_time_intervals":["test-mute"]
+          }
         }
       ]
     }

pkg/services/ngalert/api/test-data/post-rulegroup-101-export.yaml

@@ -83,3 +83,14 @@ groups:
           execErrState: Alerting
           for: 0s
           isPaused: false
+          notification_settings:
+            receiver: Test-Receiver
+            group_by:
+                - alertname
+                - grafana_folder
+                - test
+            group_wait: 1s
+            group_interval: 5s
+            repeat_interval: 5m
+            mute_time_intervals:
+                - test-mute

pkg/services/ngalert/api/test-data/post-rulegroup-101.json

@@ -109,7 +109,15 @@
           }
         ],
         "no_data_state": "NoData",
-        "exec_err_state": "Alerting"
+        "exec_err_state": "Alerting",
+        "notification_settings":{
+          "receiver":"Test-Receiver",
+          "group_by":["alertname","grafana_folder","test"],
+          "group_wait":"1s",
+          "group_interval":"5s",
+          "repeat_interval":"5m",
+          "mute_time_intervals":["test-mute"]
+        }
       }
     }
   ]