lookup license file in context path

A PE/EE licence file can currently be provided in a specific classpath or at an absolute file system path.

Due to complex class loading the class path resource is sometimes not found even if it is on the correct classpath.

For such cases an alternative lookup up inside a specific folder below /WEB-INF could provide useful fallback (or even a configurable folder)

e.g. /WEB-INF/license/zk