Refactor `service` module to TS

[jescalada]

Is your feature request related to a problem? Please describe.
The service module is one of the few that still needs to be converted to TS + ESM. Converting this would get us one step closer to a full TS conversion which improves robustness and development speed. Also, this will allow us improve test coverage for the service/routes.

Describe the solution you'd like
Convert /src/service to TS + ESM.

Describe alternatives you've considered
None

Additional context
None