FE-935: New Search UI

This branch satisfies the new search screen tabs, placeholder text, and general UI. Doesn't not include new functionality (seeing connections and requests as search results)

This is a major refactor of the previous search code.

Search screen is now a parent fragment (UserSearchFragment) that hosts the tab fragments (each a FactSearchFragment subclass) in a ViewPager. UserSearchViewModel controls the logic for the parent fragment and the child fragment tabs.

requested review from @ahmedshehata01

assigned to @kam.elixxir

changed target branch from master to FE-904_search_2_feature

marked this merge request as ready

merged