admin: Rewrite list templates

Implement the following changes:
* **Decoupling of class-based views (Djano-eztables) from urls:** There
  is only one url (/admin/json/<?type>) which multiplexes various
  class-based views. Fix apyrgio/synnefo#54.
* **Rewrite the skeleton for list templates:** With the
  Django-eztables plugin, there is no need to provide the html for table
  rows, therefore these should be rendered obsolete. Note, for the time
  being only the user page works with the new skeleton. Fix apyrgio/synnefo#53.
* **Rename all instances of "index" to "list":** Fix apyrgio/synnefo#52.
admin: Enforce format for extra JSON

This applies only to the user view.
Fix apyrgio/synnefo#49
Merge branch 'feature-admin-extra-format' into feature-admin
admin: Fix details view

Change "list" function to "catalog", since "list" conflicts with the
list() function of Python.

Fix apyrgio/synnefo#55
Merge branch 'feature-admin-fix-details' into feature-admin
admin: Rename "Restart" action to "Reboot"

Fix apyrgio/synnefo#46
admin: Set new action properties

Fix apyrgio/synnefo#40
Merge branch 'feature-admin-action-properties' into feature-admin