SSE/Alerting: First pass at query/condition translation (#31693)

- Takes the conditions property from the settings column of an alert from alerts table and turns into an ng alerting condition with the queries and classic condition.
- Has temp API rest endpoint that will take the dashboard conditions json, translate it to SEE queries + classic condition, and execute it (only enabled in dev mode).
- Changes expressions to catch query responses with a non-nil error property
- Adds two new states for an NG instance result (NoData, Error) and updates evaluation to match those states
- Changes the AsDataFrame (for frontend) from Bool to string to represent additional states
- Fix bug in condition model to accept first Operator as empty string.
- In ngalert, adds GetQueryDataRequest, which was part of execute and is still called from there. But this allows me to get the Expression request from a condition to make the "pipeline" can be built.
- Update AsDataFrame for evalresult to be row based so it displays a little better for now

pkg/expr/classic/evaluator.go

@@ -25,7 +25,7 @@ type rangedEvaluator struct {
 
 // newAlertEvaluator is a factory function for returning
 // an AlertEvaluator depending on evaluation operator.
-func newAlertEvaluator(model conditionEvalJSON) (evaluator, error) {
+func newAlertEvaluator(model ConditionEvalJSON) (evaluator, error) {
 	switch model.Type {
 	case "gt", "lt":
 		return newThresholdEvaluator(model)
@@ -54,7 +54,7 @@ func (e *thresholdEvaluator) Eval(reducedValue mathexp.Number) bool {
 	return false
 }
 
-func newThresholdEvaluator(model conditionEvalJSON) (*thresholdEvaluator, error) {
+func newThresholdEvaluator(model ConditionEvalJSON) (*thresholdEvaluator, error) {
 	if len(model.Params) == 0 {
 		return nil, fmt.Errorf("evaluator '%v' is missing the threshold parameter", model.Type)
 	}
@@ -69,7 +69,7 @@ func (e *noValueEvaluator) Eval(reducedValue mathexp.Number) bool {
 	return reducedValue.GetFloat64Value() == nil
 }
 
-func newRangedEvaluator(model conditionEvalJSON) (*rangedEvaluator, error) {
+func newRangedEvaluator(model ConditionEvalJSON) (*rangedEvaluator, error) {
 	if len(model.Params) != 2 {
 		return nil, fmt.Errorf("ranged evaluator requires 2 parameters")
 	}