[Feature] - Add Postman Workspace with all Rest Endpoints to the repo

[MariusBrill]

Is your feature request related to a problem? Please describe. As for now, we don't have our endpoints documented in any way. Hence we should create a workspace in Postman (or a similar tool) in which all endpoints including example payloads are saved. This way we as developers have a repository of all endpoints we can easily use for debug/testing and development purposes.