Public Dashboards: Query Caching (#51403)

* passes id and uid to PublicDashboardDatasource

* betterer results

* If for a public dashboard, return the PublicDashboardDataSource first or else getDatasourceSrv.get() will fail bc of no authed user.

Added some unit tests for resolving the uid from the many possible datasource types.

* updates betterer

* Exports DashboardService. Adds method to DashboardService to build anonymous user for use with public dashboards where there is no authed user. Adds method on dashboard_queries to get all dashboard uids from a dashboard.

* refactors to get unique datasource uids

* Adds tests for getting all unique datasource uids off a dashboard

* adds test for building anonymous user with read and query actions that are scoped to each datasource uid in the dashboard

* updates casing of DashboardService

* updates test case to have additional panel with a different datasource

* gives default interval to public dashboard data source

pkg/api/annotations_test.go

@@ -343,7 +343,7 @@ func postAnnotationScenario(t *testing.T, desc string, url string, routePattern
 	t.Run(fmt.Sprintf("%s %s", desc, url), func(t *testing.T) {
 		hs := setupSimpleHTTPServer(nil)
 		hs.SQLStore = store
-		hs.dashboardService = dashSvc
+		hs.DashboardService = dashSvc
 
 		sc := setupScenarioContext(t, url)
 		sc.defaultHandler = routing.Wrap(func(c *models.ReqContext) response.Response {
@@ -428,7 +428,7 @@ func deleteAnnotationsScenario(t *testing.T, desc string, url string, routePatte
 	t.Run(fmt.Sprintf("%s %s", desc, url), func(t *testing.T) {
 		hs := setupSimpleHTTPServer(nil)
 		hs.SQLStore = store
-		hs.dashboardService = dashSvc
+		hs.DashboardService = dashSvc
 
 		sc := setupScenarioContext(t, url)
 		sc.defaultHandler = routing.Wrap(func(c *models.ReqContext) response.Response {