Add search for badges, programs to the API

Fixes #236.

This adds recognition for the `search` query parameter to `/v2/badges` and `/v2/programs`. 

Currently the search is only effective against the `name` property. I can adjust that if necessary.

Note, we still don't have categorical filtering on `/v2/badges` – currently the only way to filter is with search terms. I'm not sure if the frontend of CSOL requires categorical filtering (like we have for programs – things like age range, type of activity, categories, etc.); if so, we should open another ticket for it.

@cmcavoy to review.