Previews: datasource permissions (#52747)

* Previews: datasource permissions

* lint

* simplify - force non-null `ds_uids`

* add `canBeDisabled` to search service

* add `IncludeThumbnailsWithEmptyDsUids`

* remove force refresh migration

* refactor main preview service

* add safeguard

* revert ticker interval

* update testdata

* fix test

* add mock search service

* add datasources lookup test

* update migration

* extract ds lookup to its own package to avoid cyclic imports

* lint

* fix dashbaord extract, use the real datasource lookup in tests. IS IT BULLETPROOF YET?!

* fix dashbaord extract, use the real datasource lookup in tests. IS IT BULLETPROOF YET?!

* remove stale log

* consistent casing

* pass context to `createServiceAccount`

* filter out the special grafana ds

pkg/services/searchV2/extract/testdata/check-string-datasource-id-info.json

@@ -4,7 +4,8 @@
   "tags": null,
   "datasource": [
     {
-      "uid": "-- Grafana --"
+      "uid": "grafana",
+      "type": "datasource"
     }
   ],
   "panels": [
@@ -15,7 +16,8 @@
       "pluginVersion": "7.5.0-pre",
       "datasource": [
         {
-          "uid": "-- Grafana --"
+          "uid": "grafana",
+          "type": "datasource"
         }
       ]
     }