Alerting: Add recording rules to ruler API and validation (#87779)

* Read path, main API

* Define record field for incoming requests

* Refactor several alerting specific validators into two paths

* Refactor validateCondition actually contain all the condition validation logic

* Move condition validation inside rule path

* Validators for recording rules

* Wire feature flag through to validators

* Test for accepting a valid recording rule

* Tests for negative case, no UID

* Test for ignoring alerting fields

* Build conditions based on recording rules as well

* Regenerate swagger docs

* Fix CRUD test to cover the right thing

* Re-generate swagger docs with backdated v0.30.2 version

* Regenerate base spec

* Regenerate ngalert specs

* Regenerate top level specs

* Comment and rename

* Return struct instead of modifying ref

pkg/services/ngalert/api/tooling/spec.json

@@ -5088,6 +5088,9 @@
         "provenance": {
           "$ref": "#/definitions/Provenance"
         },
+        "record": {
+          "$ref": "#/definitions/Record"
+        },
         "rule_group": {
           "type": "string"
         },
@@ -6246,6 +6249,9 @@
         "notification_settings": {
           "$ref": "#/definitions/AlertRuleNotificationSettings"
         },
+        "record": {
+          "$ref": "#/definitions/Record"
+        },
         "title": {
           "type": "string"
         },
@@ -6762,6 +6768,18 @@
         }
       }
     },
+    "Record": {
+      "type": "object",
+      "title": "Record defines how data produced by a recording rule is written.",
+      "properties": {
+        "from": {
+          "type": "string"
+        },
+        "metric": {
+          "type": "string"
+        }
+      }
+    },
     "RelativeTimeRange": {
       "description": "RelativeTimeRange is the per query start and end time\nfor requests.",
       "type": "object",
@@ -7933,6 +7951,7 @@
       }
     },
     "alertGroup": {
+      "description": "AlertGroup alert group",
       "type": "object",
       "required": [
         "alerts",
@@ -7957,7 +7976,6 @@
       "$ref": "#/definitions/alertGroup"
     },
     "alertGroups": {
-      "description": "AlertGroups alert groups",
       "type": "array",
       "items": {
         "$ref": "#/definitions/alertGroup"
@@ -8120,6 +8138,7 @@
       "$ref": "#/definitions/gettableAlert"
     },
     "gettableAlerts": {
+      "description": "GettableAlerts gettable alerts",
       "type": "array",
       "items": {
         "$ref": "#/definitions/gettableAlert"
@@ -8127,6 +8146,7 @@
       "$ref": "#/definitions/gettableAlerts"
     },
     "gettableSilence": {
+      "description": "GettableSilence gettable silence",
       "type": "object",
       "required": [
         "comment",