feat: multiple domains (#188)

* check uniqueness on create and register user

* change user email, reserve release unique email

* usergrant unique aggregate

* usergrant uniqueness

* validate UserGrant

* fix tests

* domain is set on username in all orgs

* domain in admin

* org domain sql

* zitadel domain org name

* org domains

* org iam policy

* default org iam policy

* SETUP

* load login names

* login by login name

* login name

* fix: merge master

* fix: merge master

* Update internal/user/repository/eventsourcing/user.go

Co-authored-by: Livio Amstutz <livio.a@gmail.com>

* fix: fix unique domains

* fix: rename env variable

Co-authored-by: adlerhurst <silvan.reusser@gmail.com>
Co-authored-by: Livio Amstutz <livio.a@gmail.com>

internal/org/repository/eventsourcing/eventstore_test.go

@@ -1058,7 +1058,7 @@ func TestChangesOrg(t *testing.T) {
 			},
 			res: res{
 				changes: &org_model.OrgChanges{Changes: []*org_model.OrgChange{&org_model.OrgChange{EventType: "", Sequence: 1, Modifier: ""}}, LastSequence: 1},
-				org:     &model.Org{Name: "MusterOrg", Domain: "myDomain"},
+				org:     &model.Org{Name: "MusterOrg"},
 			},
 		},
 		{