Alerting: Extract alerting rules authorization logic to a service (#77006)

* extract alerting authorization logic to separate package
* convert authorization logic to service

pkg/services/ngalert/accesscontrol/testing.go

@@ -0,0 +1,39 @@
+package accesscontrol
+
+import (
+	"context"
+
+	"github.com/grafana/grafana/pkg/services/accesscontrol"
+	"github.com/grafana/grafana/pkg/services/auth/identity"
+)
+
+type recordingAccessControlFake struct {
+	Disabled           bool
+	EvaluateRecordings []struct {
+		Permissions map[string][]string
+		Evaluator   accesscontrol.Evaluator
+	}
+	Callback func(user identity.Requester, evaluator accesscontrol.Evaluator) (bool, error)
+}
+
+func (a *recordingAccessControlFake) Evaluate(_ context.Context, ur identity.Requester, evaluator accesscontrol.Evaluator) (bool, error) {
+	a.EvaluateRecordings = append(a.EvaluateRecordings, struct {
+		Permissions map[string][]string
+		Evaluator   accesscontrol.Evaluator
+	}{Permissions: ur.GetPermissions(), Evaluator: evaluator})
+	if a.Callback == nil {
+		return evaluator.Evaluate(ur.GetPermissions()), nil
+	}
+	return a.Callback(ur, evaluator)
+}
+
+func (a *recordingAccessControlFake) RegisterScopeAttributeResolver(prefix string, resolver accesscontrol.ScopeAttributeResolver) {
+	// TODO implement me
+	panic("implement me")
+}
+
+func (a *recordingAccessControlFake) IsDisabled() bool {
+	return a.Disabled
+}
+
+var _ accesscontrol.AccessControl = &recordingAccessControlFake{}