Added functionality to delete Sigmets
Added functionality to delete Sigmets

KNMI/GeoWeb-FrontEnd,maartenplieger/GeoWeb-FrontEnd,diMosellaAtWork/GeoWeb-FrontEnd,KNMI/GeoWeb-FrontEnd,diMosellaAtWork/GeoWeb-FrontEnd,KNMI/GeoWeb-FrontEnd,maartenplieger/GeoWeb-FrontEnd