We should add a site checker that checks that a site is ok
Could be launch

• at startup for all sites
• optionnaly all nights for all sites
• each time a site conf is modified
• manually on one or more site

for auto launch a mail will be sent
for manul a screen could propose modifications

This should be an extension point

Exemples of checks :

• the cyclic redirections (is manually done for the moment, cpild be migrated here)
• the skin association with a site (search if all used templates exists, and if all zones used does exists)
• ...

A modification screen should then propose to fix this