theme: set home page search box width smaller
theme: set home page search box width smaller

We can't afford 400 pixels of search entry at smaller resolutions,
we don't have a good responsive solution at the moment so we will
just drop the size
https://phabricator.endlessm.com/T12361

endlessm/eos-knowledge-lib,endlessm/eos-knowledge-lib,endlessm/eos-knowledge-lib,endlessm/eos-knowledge-lib