Schedule updates to our routes in our GenServer state

[samhstn]

Currently our GenServer keeps the data about our routes in its state, but we don't have a way to update it.

We should:

• periodically update the router data (or uncache it) - this would involve checking our s3 buckets or urls for updates.
• perform more frequent checks for routes which are frequently visited, and check less often for routes which aren't visited.