fix(core): Fix broken startup and improve organization

[iambriccardo]

This PR improves the structure of the replicator, fixes the configcat panic which would happen since configcat was initialized outside of the tokio runtime, improves logs and implements a more efficient JSON writer for logs that avoids parsing logs to mutate them every time.

[coveralls]

coverage: 77.929% (-0.03%) from 77.954%
when pulling 80a3f15 on fix-startup
into b47d296 on main.