Add admin ability to create an access token on behalf of another user

A customer wants to maintain a fully IaC-enabled approach to installing 3scale. Therefore, they manage through curl-triggered rest calls to create an administrative user.

They did this with the ADMIN_ACCESS_TOKEN taken from the system-seed secret. Now they need to know a method / to create a personal access token in an automate way.

The Personal Access Token Create API does not accept an UserID, but needs a mandatory access token as well. So there is no UserName/Password-based (basic-auth) call for creating a personal access token.

So the request is add admin ability to create an access token on behalf of another user.