groups templates improvements

- require confirmation before removing a member
- require confirmation before removing self
- make button text less verbose
- use more standardised formatting for group editing form
- improve button colours
- add missing trans tags
- reload group page when removing member

bookwyrm/templates/groups/find_users.html

@@ -5,5 +5,5 @@
     <h2 class="title is-5">
         {% trans "Add new members!" %}
     </h2>
-    {% include 'groups/suggested_users.html' with suggested_users=suggested_users query=query %}
+    {% include 'groups/suggested_users.html' with suggested_users=suggested_users %}
 {% endblock %}