Create user management functionality (#152)

* Create user management page
* Remove old user creating UI
* Add username validation; admin user auto-creation
* Provide docs on user management
* Bump version

libs/ktem/ktem/assets/css/main.css

@@ -28,7 +28,7 @@ footer {
     border: none !important;
 }
 
-#chat-tab, #settings-tab, #help-tab {
+#chat-tab, #settings-tab, #help-tab, #admin-tab {
     border: none !important;
 }