Document what settings are only available via the IBM Cloud Console (UI)

In attempting to build automation to create new enterprise accounts, and set them up, it was discovered there's some account settings that are only available in the IBM Cloud Console (ie the Web UI), but not available to be set programmatically (via CLI, REST or terraform).

This adds unwanted manual steps when creating new IBM Cloud accounts for departments and/or groups.

A couple of examples:

https://cloud.ibm.com/docs/account?topic=account-restrict-acct-invite

https://cloud.ibm.com/account/notifications-distribution-list