Alerting: Add endpoint to revert to a previous alertmanager configuration (#65751)

* Alerting: Add endpoint to revert to a previous alertmanager configuration

This endpoint is meant to be used in conjunction with /api/alertmanager/grafana/config/history to
revert to a previously applied alertmanager configuration. This is done by ID instead of raw config
string in order to avoid secure field complications.

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

@@ -3644,6 +3644,7 @@
    "type": "object"
   },
   "alertGroup": {
+   "description": "AlertGroup alert group",
    "properties": {
     "alerts": {
      "description": "alerts",
@@ -3667,6 +3668,7 @@
    "type": "object"
   },
   "alertGroups": {
+   "description": "AlertGroups alert groups",
    "items": {
     "$ref": "#/definitions/alertGroup"
    },
@@ -3771,6 +3773,7 @@
    "type": "object"
   },
   "gettableAlert": {
+   "description": "GettableAlert gettable alert",
    "properties": {
     "annotations": {
      "$ref": "#/definitions/labelSet"
@@ -3826,13 +3829,13 @@
    "type": "object"
   },
   "gettableAlerts": {
-   "description": "GettableAlerts gettable alerts",
    "items": {
     "$ref": "#/definitions/gettableAlert"
    },
    "type": "array"
   },
   "gettableSilence": {
+   "description": "GettableSilence gettable silence",
    "properties": {
     "comment": {
      "description": "comment",
@@ -3881,12 +3884,14 @@
    "type": "object"
   },
   "gettableSilences": {
+   "description": "GettableSilences gettable silences",
    "items": {
     "$ref": "#/definitions/gettableSilence"
    },
    "type": "array"
   },
   "integration": {
+   "description": "Integration integration",
    "properties": {
     "lastNotifyAttempt": {
      "description": "A timestamp indicating the last attempt to deliver a notification regardless of the outcome.\nFormat: date-time",
@@ -4068,7 +4073,6 @@
    "type": "object"
   },
   "receiver": {
-   "description": "Receiver receiver",
    "properties": {
     "active": {
      "description": "active",