Similarly what we did within #38566 we should consider adding map-roles-members scope to group resource type.

Today, when administrator wants to delegate ability to map-roles to users, it has to be done either for all realm users or per individual users or set of users.

For instance, if a realm administrator gets administrative access of a group and on top of that he needs to be able assign a role to the group members, server administrator would need to update permissions every time when new group member is created.