[manage view] cleanup manage view and user menu * drop code that shouldn't be there (e.g. folders handling) * add a section displaying site management actions, some of them were initially in the user's drop down menu, which now only have a 'manage' link with regards to management actions * stop displaying 'system' and 'schema' entities by default, only 'application' entities * put 'gc', 'registry' and 'info' views as tabs of a generic 'server information' view