IAM: Create and delete user from the legacy store (#107694)

* Add Create for User + DualWriter setup

* Add delete User

* Fix delete + access check

* Add tests for delete user

* Add tests for create user

* Fixes

* Use sqlx session to fix database locked issues

* wip authz checks

* legacyAccessClient

* Update legacyAccessClient, add tests for create user

* Close rows before running other queries

* Use ExecWithReturningId

* Verify deletion in the tests

* Add Validate and Mutate

* Other changes

* Address feedback

* Update tests

---------

Co-authored-by: Gabriel Mabille <gabriel.mabille@grafana.com>

apps/iam/kinds/user.cue

@@ -16,6 +16,13 @@ user: {
 
 	versions: {
 		"v0alpha1": {
+			validation: {
+				operations: [
+					"CREATE",
+					"UPDATE",
+				]
+			}
+
 			schema: {
 				spec: v0alpha1.UserSpec
 			}

apps/iam/pkg/apis/iam_manifest.go

@@ -14,6 +14,8 @@ import (
 	v0alpha1 "github.com/grafana/grafana/apps/iam/pkg/apis/iam/v0alpha1"
 )
 
+var ()
+
 var appManifestData = app.ManifestData{
 	AppName: "iam",
 	Group:   "iam.grafana.app",
@@ -91,6 +93,14 @@ var appManifestData = app.ManifestData{
 			Versions: []app.ManifestKindVersion{
 				{
 					Name: "v0alpha1",
+					Admission: &app.AdmissionCapabilities{
+						Validation: &app.ValidationCapability{
+							Operations: []app.AdmissionOperation{
+								app.AdmissionOperationCreate,
+								app.AdmissionOperationUpdate,
+							},
+						},
+					},
 				},
 			},
 		},