Add dendrite support to cypress tests (#9884)

* Minimum hacks required to run cypress tests with dendrite

* Remove wget hack since dendrite containers now have curl

* Add basic dendritedocker plugin & hack into login spec for testing

* Add generic HomeserverInstance interface

* Add env var to configure which homeserver to use

* Remove synapse specific homeserver support api

* Update the rest of the tests to use HomeserverInstance

* Update cypress docs to reference new homeserver abstraction

* Fix formatting issues

* Change dendrite to use main branch container

cypress/plugins/utils/homeserver.ts

@@ -0,0 +1,28 @@
+/*
+Copyright 2023 The Matrix.org Foundation C.I.C.
+
+Licensed under the Apache License, Version 2.0 (the "License");
+you may not use this file except in compliance with the License.
+You may obtain a copy of the License at
+
+    http://www.apache.org/licenses/LICENSE-2.0
+
+Unless required by applicable law or agreed to in writing, software
+distributed under the License is distributed on an "AS IS" BASIS,
+WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+See the License for the specific language governing permissions and
+limitations under the License.
+*/
+
+/// <reference types="cypress" />
+
+export interface HomeserverConfig {
+    configDir: string;
+    registrationSecret: string;
+    baseUrl: string;
+    port: number;
+}
+
+export interface HomeserverInstance extends HomeserverConfig {
+    serverId: string;
+}