Add caching where doable to reduce server load

[devinmatte]

Motivation

Reduce calls to API gateway, which will lower cost and server load (as well as local web traffic usage) and will make the page seem faster to users

Changes

• Add day and week cache to basically static data
• Increase from 10s refresh intervals to 15s to reduce API gateway load without meaningfully impacting usability
• Add cache to other calls both backend and frontend to reduce extra calls

Testing Instructions