AlertingNG: Unified alerting API mock (#32040)

* AlertingNG: Alertmanager mock API

* AlertingNG: Remove permissions API routes

* Add example POST payloads

* Prometheus and testing mock API

pkg/services/ngalert/api/util.go

@@ -3,6 +3,8 @@ package api
 import (
 	"fmt"
 	"regexp"
+
+	"github.com/go-openapi/strfmt"
 )
 
 var searchRegex = regexp.MustCompile(`\{(\w+)\}`)
@@ -13,3 +15,15 @@ func toMacaronPath(path string) string {
 		return []byte(fmt.Sprintf(":%s", m))
 	}))
 }
+
+func timePtr(t strfmt.DateTime) *strfmt.DateTime {
+	return &t
+}
+
+func stringPtr(s string) *string {
+	return &s
+}
+
+func boolPtr(b bool) *bool {
+	return &b
+}