[lib] Add reports service facts

Summary:
Similiar to other services, add facts file with endpoint info for reports service.
We expose only single endpoint meaningful to clients. Other endpoints are staff only so I haven't added them.

Test Plan: flow

Reviewers: kamil, michal, tomek, inka

Reviewed By: tomek

Subscribers: ashoat

Differential Revision: https://phab.comm.dev/D9041