Synnefo

Helpdesk improvements

- New json view to return a list of existing users with a prefix ending
with "@" to be used for autocompletion in helpdesk account name input.
- Proper non existing account handling. If no vms or private networks exist
for the specified account notify helpdesk user that the account...

Helpdesk authentication view wrapper fix

- avoid AttributeError when checking for request.user attribute to be
present
- deny access if no groups defined in user dict

Helpdesk permissions and filters

- deny access to users that don't belong to 'helpdesk' group
- filter results based on account provided

Fix create view image selection, Refs #2487

Only reset image selection on create view initialization to be able to
keep image selection between subviews transitions.

Improve wording on vm create view

More explanatory info for the selection of public keys that will get
copied to the created vm on step 3 of vm create view. Refs, #2462