Search functionality for lists

[escottalexander]

Closely related to #84 and should utilize the same search functionality.
Placeholder text in the search bar should be "Search Lists".

A user should be able to type any string and see lists sorted by whether

1. Title contains the string
2. Description contains the string

OR if string ends in ".eth" it searches for a list creator who's ENS matches the entered string. This probably means we should save the list creators ENS to the database instead of just their address.

Lists that don't contain the string should not show at all.