Cache results from Swiftype to avoid re-searching related content on every page load

[jerelmiller]

Description

Swiftype's API comes at a cost. We have a limit to the number of searches we can do via Swiftype before we are charged for more usage. To try and keep cost down and avoid unnecessary search requests, we need to implement some kind of caching mechanism for the results so that visiting guide pages incur as least cost as possible.

TODO:

We need to define how we want to cache the results. We can use something like the browser's local storage, or something like service workers to cache network requests on a per-user basis. Another alternative would be to fetch the results during the build and add the results to the GraphQL schema, which means we only incur cost when the site builds.

[jerelmiller]

Closing this ticket as this is better captured in #582 and #589