feat: v2alpha user service idp endpoints (#5879)

* feat: v2alpha user service idp endpoints

* feat: v2alpha user service intent endpoints

* begin idp intents (callback)

* some cleanup

* runnable idp authentication

* cleanup

* proto cleanup

* retrieve idp info

* improve success and failure handling

* some unit tests

* grpc unit tests

* add permission check AddUserIDPLink

* feat: v2alpha intent writemodel refactoring

* feat: v2alpha intent writemodel refactoring

* feat: v2alpha intent writemodel refactoring

* provider from write model

* fix idp type model and add integration tests

* proto cleanup

* fix integration test

* add missing import

* add more integration tests

* auth url test

* feat: v2alpha intent writemodel refactoring

* remove unused functions

* check token on RetrieveIdentityProviderInformation

* feat: v2alpha intent writemodel refactoring

* fix TestServer_RetrieveIdentityProviderInformation

* fix test

* i18n and linting

* feat: v2alpha intent review changes

---------

Co-authored-by: Livio Spring <livio.a@gmail.com>
Co-authored-by: Tim Möhlmann <tim+github@zitadel.com>

internal/domain/idp.go

@@ -91,3 +91,22 @@ func (t IDPType) DisplayName() string {
 		return ""
 	}
 }
+
+type IDPIntentState int32
+
+const (
+	IDPIntentStateUnspecified IDPIntentState = iota
+	IDPIntentStateStarted
+	IDPIntentStateSucceeded
+	IDPIntentStateFailed
+
+	idpIntentStateCount
+)
+
+func (s IDPIntentState) Valid() bool {
+	return s >= 0 && s < idpIntentStateCount
+}
+
+func (s IDPIntentState) Exists() bool {
+	return s != IDPIntentStateUnspecified && s != IDPIntentStateFailed //TODO: ?
+}