Alerting: Rule backtesting with experimental UI (#115525)

* add function to convert StateTransition to LokiEntry
* add QueryResultBuilder
* update backtesting to produce result similar to historian
* make shouldRecord public
* filter out noop transitions
* add experimental front-end
* add new fields
* move conversion of api model to AlertRule to validation
* add extra labels
* calculate tick timestamp using the same logic as in scheduler
* implement correct logic of calculating first evaluation timestamp
* add uid, group and folder uid they are needed for jitter strategy

* add JitterOffsetInDuration and JitterStrategy.String()

* add config `backtesting_max_evaluations` to [unified_alerting] (not documented for now)

* remove obsolete tests

* elevate permisisons for backtesting endpoint
* move backtesting to separate dir

pkg/tests/api/alerting/api_backtesting_test.go

@@ -68,7 +68,7 @@ func TestBacktesting(t *testing.T) {
 			require.Truef(t, ok, "The data file does not contain a field `data`")
 
 			status, body := apiCli.SubmitRuleForBacktesting(t, request)
-			require.Equal(t, http.StatusOK, status)
+			require.Equalf(t, http.StatusOK, status, "Response: %s", body)
 			var result data.Frame
 			require.NoErrorf(t, json.Unmarshal([]byte(body), &result), "cannot parse response to data frame")
 		})
@@ -107,6 +107,7 @@ func TestBacktesting(t *testing.T) {
 			resourcepermissions.SetResourcePermissionCommand{
 				Actions: []string{
 					accesscontrol.ActionAlertingRuleRead,
+					accesscontrol.ActionAlertingRuleUpdate,
 				},
 				Resource:          "folders",
 				ResourceID:        "*",