API SSO, Beautification of Tables, and more. (#562)

# One Thousandth Commit 🎉 🎈 🎆 🍾

* Allow requiring API ownership validation by SSO.
Closes #163

* Add Discourse group name length restrictions.

* Redirect after api addition/deletion of main character

* Correct admin searching for removed discourse_username field in AuthServicesInfo

* Correct admin function to sync user Discourse groups

* Beautify tables by removing borders and hiding when empty.

*Add buttons on dead-end pages to return to originating view.

services/managers/discourse_manager.py

@@ -343,7 +343,10 @@ class DiscourseManager:
     @staticmethod
     def _sanitize_groupname(name):
         name = name.strip(' _')
-        return re.sub('[^\w]', '', name)
+        name = re.sub('[^\w]', '', name)
+        if len(name) < 3:
+            name = name + "".join('_' for i in range(3-len(name)))
+        return name[:20]
 
     @staticmethod
     def update_groups(user):