Revert "re #186: Add UserAbstract::hasRole and UserAbstract::hasRoles"

This reverts commit 9f94a671a9454d6b6714826e154ba64f474ff556.
Revert "re #186: Add UserInterface::hasRole and hasRoles"

This reverts commit b250e5899f78e9aec80a13f3789208278853682b.