powerusers group is missing from the User/Groups default contribution

When you try to define users or groups using the "Roles & Permissions / User & Groups" feature/page, you have a few default values provided:

1. [User] Administrator
2. [Group] members
3. [Group] administrators

Yet the "powerusers" group entry is missing.
We should add it, as deploying such a configuration will otherwise erase it given that you select the "always" deployment option.

AC
When creating users and groups in Studio, default values contain

1. [User] Administrator
2. [Group] members
3. [Group] administrators
4. [Group] powerusers