Resolve "Compatibility with Shibboleth SP"

Closes #111

See merge request reg-app/reg-app!22

eliminates the need for an external metadata url for SPs

Resolve "Refactor group API"

Closes #110

See merge request reg-app/reg-app!21

Refactoring and introduction of scripted group hook. Needs change on
interface.

For easy access within rules and scripts

Property was removed

create some text properties