Add Maestro tests for create & join rooms (#472)

I created 2 additional test users to use them as MXID we lookup during room creation.

I.e. we will not login as those users, it's just 2 known MXIDs that we know exist so we can look them up.

- https://github.com/vector-im/element-x-android/issues/409

.maestro/README.md

@@ -23,9 +23,11 @@ From root dir of the project
 ```shell
 maestro test \
     -e APP_ID=io.element.android.x.debug \
-    -e USERNAME=user \
+    -e USERNAME=user1 \
     -e PASSWORD=123 \
     -e ROOM_NAME="MyRoom" \
+    -e INVITEE1_MXID=user2 \
+    -e INVITEE2_MXID=user3 \
     .maestro/allTests.yaml
 ```