new endpoint to post/get trimmed dashboard json (#33465)

* new endpoint to post/get trimed dashboard json

* add isdisabled check in dashboard.go

pkg/schema/load/testdata/artifacts/dashboards/trimdefault/test1

@@ -0,0 +1,35 @@
+Verifies common usecases for trimdefault/applydefault functions:
+* Basic cases
+* Real dashboard
+
+-- CUE --
+{ 
+  id?: number
+  uid: string
+  gnetId?: string
+  style: *"light" | "dark"
+  timezone?: *"browser" | "utc"
+  editable: bool | *true
+  schemaVersion: number | *25
+  version?: number
+  graphTooltip: >=0 & <=2 | *0
+}
+
+-- Full --
+{
+  "id": 42,
+  "uid": "emal8gQMz",
+  "style": "light",
+  "editable": true,
+  "schemaVersion": 27,
+  "version": 2,
+  "graphTooltip": 0
+}
+
+-- Trimed --
+{
+  "id": 42,
+  "uid": "emal8gQMz",
+  "schemaVersion": 27,
+  "version": 2
+}

pkg/schema/load/testdata/artifacts/dashboards/trimdefault/test2

@@ -0,0 +1,41 @@
+Verifies common usecases for trimdefault/applydefault functions:
+* Basic cases
+* Real dashboard
+
+-- CUE --
+{ 
+  timepicker?: {
+      collapse: bool | *false
+      enable: bool | *true
+      hidden: bool | *false
+      refresh_intervals: [...string] | *["5s", "10s", "30s", "1m", "5m", "15m", "30m", "1h", "2h", "1d"]
+  }
+}
+
+-- Full --
+{
+  "timepicker": {
+    "collapse": true,
+    "enable":true,
+    "hidden":false,
+    "refresh_intervals":[
+      "5s",
+      "10s",
+      "30s",
+      "1m",
+      "5m",
+      "15m",
+      "30m",
+      "1h",
+      "2h",
+      "1d"
+    ]
+  }
+}
+
+-- Trimed --
+{
+  "timepicker": {
+    "collapse": true
+  }
+}

pkg/schema/load/testdata/artifacts/dashboards/trimdefault/test3

@@ -0,0 +1,46 @@
+Verifies common usecases for trimdefault/applydefault functions:
+* Nested struct
+* Simple array
+
+-- CUE --
+{ 
+  annotations?: list: [...{
+      builtIn: number | *0
+      datasource: string
+      enable?: bool | *true
+      hide?: bool | *false
+      iconColor?: string
+      name?: string
+      type: string | *"dashboard"
+      rawQuery?: string
+      showIn:   number | *0
+  }]
+}
+
+-- Full --
+{
+  "annotations": {
+    "list": [
+      {
+        "builtIn": 1,
+        "datasource": "-- Grafana --",
+        "name": "Annotations & Alerts",
+        "type": "dashboard",
+        "showIn": 0
+      }
+    ]
+  }
+}
+
+-- Trimed --
+{
+  "annotations": {
+    "list": [
+      {
+        "builtIn": 1,
+        "datasource": "-- Grafana --",
+        "name": "Annotations & Alerts"
+      }
+    ]
+  }
+}