Integrate UIN generation with a real MOSIP instance

[naftis]

Currently, the deployment is using mosip-mock, and we haven't tested with an actual MOSIP installation. MOSIP might not use similar naming as our mock API.

Let's align these and start testing with an actual MOSIP Collab environment. If there are obvious improvements or needs in MOSIP-side mediator routes or payloads, let's try to push MOSIP to update, but let's prepare to need to do the changes to our end.