Server start fails if DOAG REST resource unavailable

[ascheman]

Currently we see server startup failures since a JSON datasource is not availble (the mentioned URL returns a 404 error):

Application startup failed
org.springframework.beans.factory.BeanCreationException: Error creating bean with name 'eventBookingResource' defined in URL [jar:file:/opt/dukecon/dukecon.war!/WEB-INF/classes!/org/dukecon/server/conference/EventBookingResource.class]: Bean instantiation via constructor 
failed; nested exception is org.springframework.beans.BeanInstantiationException: Failed to instantiate [org.dukecon.server.conference.EventBookingResource]: Constructor threw exception; nested exception is java.io.FileNotFoundException: https://www.javaland.eu/de/api/referenten_exadata.php?key=JL-EOPTGB-DR
        at org.springframework.beans.factory.support.ConstructorResolver.autowireConstructor(ConstructorResolver.java:279)