Link to the SelfService asset page when rendered on SelfService/Display.html

Giving Unprivileged users a link to /Asset/Display.html fails.
Make asset links target SelfService for Unprivileged users

In particular, this shows up in Ticket History on
/SelfService/Display.html
Hide "Add an asset" box unless the user has ModifyTicket
Don't link to asset Modify pages if the user only has SelfService
Merge branch '1.0/selfservice-links'