Revert "Fixes #4972: Correct the documentation about user management to sync with rudder-users.xml base file change"

This reverts commit ec213c0b09dfd94b4b6cd7cb0eea26707d8f3a08.
Fixes #4960: Correct the documentation about user management and add role examples

This commit is a cherry-pick of ec213c0b09dfd94b4b6cd7cb0eea26707d8f3a08 with a proper commit name.
Merge branch 'branches/rudder/2.6' into branches/rudder/2.10