Feature: Move caching into server's redis instance

[its-saanvi]

Problem

The current in-memory caching system is not very efficient in re-initializing for a large amount of servers (takes about 3m for all 150 servers to re-init in the 1.16 bot).

Solution

Move the in-memory caching system into the redis instance on the server.

Create sub-issues against this main issue to track the different components that might need changing.