Prior to this change authorities are always mapped using well known
claim names ('scope' or 'scp'). To change this default behaviour the
converter had to be replaced completely with a custom one.
This commit adds an additional setter to configure a custom
claim name like e.g. 'roles'. Without specifying a custom claim name
the default claims to be used still remains to the well known ones.
This way the authorities can be mapped according to customized
token claims.
Fixes gh-7100
0a058c973a