Refactor ShowRequestorTickets

This starts to convert it to be a generic "Tickets related to a
user" list.  Aside from the copy, it changes:
    Title passed in
    renames the Requestor argument to User
    Changes the default search to Watcher rather than Requestor
Rename a callback we added to master in 225eb0970a85

This pushes the title modification part of it up into
ShowRequestorTickets and gives a name to the remaining QueryProperty
callback in TicketList
Allow extensions to modify what kind and which Users we search for.

This also allows some arbitrary FromSQL frobbing if you really want it.
Allow the ticket list to optionally be in a Title Box
Pull format out into MoreAboutRequestorTicketListFormat

This lets you reformat your More About Requestor lists from the config
file.
Merge branch '4.2/user-ticket-list-refactor'