Geocoding SDK (MAPCO-4537)

Recently, users have reached out to us asking to be able, in their front-end applications, to show which control tile the user's mouse is on. This is essentially a simple Latitude-Longitude to Control Tile conversion.
Obviously, we can't handle so many conversion requests. But, we can't also send them conversion table that might change from time to time.
That's why, we want to build an SDK. On SDK's startup, It will pull locally the conversion table from a public S3 bucket. From time to time, it will refresh the table (We can start in every one hour). We should use [https://github.com/mcollina/async-cache-dedupe](`async-cache-dedupe`) package.
If we create an SDK, we should also fetch the routes for the user.

TODO: add further information and a design.

Start by clarifying the SDK design, including the startup fetch from the public S3 bucket, hourly table refresh, latitude-longitude conversion, and route fetching. Review async-cache-dedupe and define acceptance criteria for the SDK before locating implementation entry points; the issue's TODO indicates that the design is not yet settled.

Written by the indexing model from the issue text.