Marker Roles feature needs naming changes, to eliminate confusion.

[JakenVeina]

E.G.

The role designation should be something like Subscribable or MarkerRole, not Pingable. The role being "pingable" has nothing to do with the functionality that MODiX is providing, and conflicts directly with the Restricted Mentioning feature, which actually DOES make a role functionally "pingable" or not. We've already had at least one third-party user get the config wrong, and come ask us about it.

By extension, all the commands, aliases, and documentations on the module need to be changed.

[thaumanovic]

Would be made obsolete by #973