[bug 1039523] Infrastructure for instant search

This does several things:
- Adds nunjucks and grunt to NPM dependencies
- Adds a `Gruntfile` to create grunt tasks to make development easier
- Adds a new manager command to precompile nunjucks templates
- Updates travis and deploy scripts to precompile nunjucks templates
- Updates the search view to return more consistent data in JSON format

r?
I'm not opposed to gulp and it does make sense to use one tool across products. I'll make the switch.