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/model/domain.go

@@ -0,0 +1,18 @@
+package model
+
+import es_models "github.com/caos/zitadel/internal/eventstore/models"
+
+type OrgDomain struct {
+	es_models.ObjectRoot
+	Domain   string
+	Primary  bool
+	Verified bool
+}
+
+func NewOrgDomain(orgID, domain string) *OrgDomain {
+	return &OrgDomain{ObjectRoot: es_models.ObjectRoot{AggregateID: orgID}, Domain: domain}
+}
+
+func (domain *OrgDomain) IsValid() bool {
+	return domain.AggregateID != "" && domain.Domain != ""
+}