delete user

WP [#17654](https://community.openproject.org/work_packages/17654)

Requires merging of #2325
`feature/multitenacy` already contains a delayed job object for user deletion used here: https://github.com/opf/openproject/blob/feature/multitenancy/app/controllers/users_controller.rb#L279
it's defined here: https://github.com/opf/openproject/blob/feature/multitenancy/app/workers/delete_user_job.rb