Using the search box creates a query against the pns,
summaries, descriptions and filenames of recipes.
This results in a lot of spurious results for common terms
like "git" when performing a recipe search.
Make the results more useful by:
* Only searching against pn, description and summary (not file).
* Putting matches against pn at the top of the list, followed by
matches against description and summary.
[YOCTO #9159]
Signed-off-by: Elliot Smith <elliot.smith@intel.com>