Provide public REST APIs for user management as in server

Summary

Please provide a public REST API for user management specifically:

1. /user - PUT - to update display-name
2. /user/activate - POST to activate a user
3. /user/deactivate - POST to deactivate a user

Which supports API Token, OAuth, etc.

Background

Currently vendor uses a private rest API /admin/rest/um/1 to do their bidding and that they can do the same in server as well.