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/preferences_test.go

@@ -40,7 +40,7 @@ func TestAPIEndpoint_GetCurrentOrgPreferences_LegacyAccessControl(t *testing.T)
 		q.Result = &models.Dashboard{Uid: "home", Id: 1}
 	}).Return(nil)
 
-	sc.hs.dashboardService = dashSvc
+	sc.hs.DashboardService = dashSvc
 
 	prefService := preftest.NewPreferenceServiceFake()
 	prefService.ExpectedPreference = &pref.Preference{HomeDashboardID: 1, Theme: "dark"}
@@ -169,7 +169,7 @@ func TestAPIEndpoint_PatchUserPreferences(t *testing.T) {
 		q := args.Get(1).(*models.GetDashboardQuery)
 		q.Result = &models.Dashboard{Uid: "home", Id: 1}
 	}).Return(nil)
-	sc.hs.dashboardService = dashSvc
+	sc.hs.DashboardService = dashSvc
 	t.Run("Returns 200 on success", func(t *testing.T) {
 		response := callAPI(sc.server, http.MethodPatch, patchUserPreferencesUrl, input, t)
 		assert.Equal(t, http.StatusOK, response.Code)