Update server list in config.json (#947)

* remove kde.org from config

because they have disabled registrations, which is required to be listed on login.register page.

* remove halogen.city

seems dead hs now

* add converser.eu

seems to be working again

* Update config.json

* halogen.city is back

config.json

@@ -1,9 +1,9 @@
 {
   "defaultHomeserver": 3,
   "homeserverList": [
+    "converser.eu",
     "envs.net",
     "halogen.city",
-    "kde.org",
     "matrix.org",
     "mozilla.org"
   ],