Add Option to Restrict Access to "Roles" to ProMasters Only

As there is potential for sensitive information to be included in the Roles section (i.e. Annual Salaries), it would be useful to have the option in the Configuration settings to restrict access to the Roles to ProMasters only. This way, the ProMasters can add/amend roles and salaries as required.

This restricted access could also be extended to Systems, Glossary, and Tags if necessary.