make project_issue default views respect "sticky"

The problem is that the views work via table sort. So, it's not clear how to respect sorting first by sticky, then by whatever the currently active tablesort is.

The sort order is also slightly complicated by the fact that if you have an active search term, we default to sorting by the search relevance. There's some magic there.

Anyway, sticky is tricky... ;)

Seems like anytime you search sticky would no longer apply to the sort. As for any tablesort or otherwise, I think just having the sticky reflected in the default sort, when landing on the issues page for a project would be an improvement.

I agree with mikey_p's suggestion.

#472650: Let project issue view respect the "sticky" flag