Alerting: extend rules export API to filter by folder and group (#74423)

update endpoint `GET /api/v1/provisioning/alert-rules/export` to accept query parameters `folderUid` and `group`

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

@@ -1877,6 +1877,18 @@
             "description": "Format of the downloaded file, either yaml or json. Accept header can also be used, but the query parameter will take precedence.",
             "name": "format",
             "in": "query"
+          },
+          {
+            "type": "string",
+            "description": "UID of folder from which export rules",
+            "name": "folderUid",
+            "in": "query"
+          },
+          {
+            "type": "string",
+            "description": "Name of group of rules to export. Must be specified only together with folder UID",
+            "name": "group",
+            "in": "query"
           }
         ],
         "responses": {
@@ -6913,7 +6925,6 @@
       }
     },
     "alertGroup": {
-      "description": "AlertGroup alert group",
       "type": "object",
       "required": [
         "alerts",
@@ -7044,7 +7055,6 @@
       }
     },
     "gettableAlert": {
-      "description": "GettableAlert gettable alert",
       "type": "object",
       "required": [
         "labels",
@@ -7101,7 +7111,6 @@
       "$ref": "#/definitions/gettableAlert"
     },
     "gettableAlerts": {
-      "description": "GettableAlerts gettable alerts",
       "type": "array",
       "items": {
         "$ref": "#/definitions/gettableAlert"
@@ -7109,7 +7118,6 @@
       "$ref": "#/definitions/gettableAlerts"
     },
     "gettableSilence": {
-      "description": "GettableSilence gettable silence",
       "type": "object",
       "required": [
         "comment",
@@ -7159,7 +7167,6 @@
       "$ref": "#/definitions/gettableSilence"
     },
     "gettableSilences": {
-      "description": "GettableSilences gettable silences",
       "type": "array",
       "items": {
         "$ref": "#/definitions/gettableSilence"