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/string-datasource-variable-info.json

@@ -7,7 +7,7 @@
   ],
   "datasource": [
     {
-      "uid": "SQLite Grafana",
+      "uid": "sqlite-1",
       "type": "sqlite-datasource"
     }
   ],
@@ -19,7 +19,7 @@
       "pluginVersion": "9.1.0-pre",
       "datasource": [
         {
-          "uid": "SQLite Grafana",
+          "uid": "sqlite-1",
           "type": "sqlite-datasource"
         }
       ]