Allow all users in a specific group to use MaxAdmin

In MaxScale 2.1, Linux user accounts can be given access to maxadmin:

https://mariadb.com/kb/en/mariadb-enterprise/mariadb-maxscale-21-maxadmin-admin-interface/#working-with-administration-interface-users

Some users would like this to be expanded, so that all Linux users within a specific Linux group could be given access to maxadmin. e.g. executing something like this would allow any user in the "dba" group to use MaxAdmin:

MaxScale> enable group dba

It would be preferable if this would also work for non-local groups pulled in from certain PAM plugins, such as those from Active Directory or LDAP.