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/post.json

@@ -1573,6 +1573,9 @@
     "provenance": {
      "$ref": "#/definitions/Provenance"
     },
+    "record": {
+     "$ref": "#/definitions/Record"
+    },
     "rule_group": {
      "type": "string"
     },
@@ -2730,6 +2733,9 @@
     "notification_settings": {
      "$ref": "#/definitions/AlertRuleNotificationSettings"
     },
+    "record": {
+     "$ref": "#/definitions/Record"
+    },
     "title": {
      "type": "string"
     },
@@ -3247,6 +3253,18 @@
    "title": "ReceiverExport is the provisioned file export of alerting.ReceiverV1.",
    "type": "object"
   },
+  "Record": {
+   "properties": {
+    "from": {
+     "type": "string"
+    },
+    "metric": {
+     "type": "string"
+    }
+   },
+   "title": "Record defines how data produced by a recording rule is written.",
+   "type": "object"
+  },
   "RelativeTimeRange": {
    "description": "RelativeTimeRange is the per query start and end time\nfor requests.",
    "properties": {
@@ -4418,6 +4436,7 @@
    "type": "object"
   },
   "alertGroup": {
+   "description": "AlertGroup alert group",
    "properties": {
     "alerts": {
      "description": "alerts",
@@ -4441,7 +4460,6 @@
    "type": "object"
   },
   "alertGroups": {
-   "description": "AlertGroups alert groups",
    "items": {
     "$ref": "#/definitions/alertGroup"
    },
@@ -4602,12 +4620,14 @@
    "type": "object"
   },
   "gettableAlerts": {
+   "description": "GettableAlerts gettable alerts",
    "items": {
     "$ref": "#/definitions/gettableAlert"
    },
    "type": "array"
   },
   "gettableSilence": {
+   "description": "GettableSilence gettable silence",
    "properties": {
     "comment": {
      "description": "comment",