Here you go: https://rest.openmrs.org/
Some of the endpoints you are looking for might not yet exist.
From wiki page of your project:
" * For those administration features that do not have existing REST endpoints, create (or coordinate with the GSoC 2021: The REST of Administration project to create) those endpoints by extending the REST Module.".
By the way, I’m doing the project “The REST of Administration” this year, and I am now going to focus on discovering endpoints that do not yet exist, so feel free to reach out to me if you want to have some implemented