Added configuration for h2 db (for development use) in pom.xml and jetty.
All dependencies for the h2 db and the corresponding datasource must be in the classpath of jetty.
No need for a local h2 db server.
DB file is saved in ~/h2db_file.

Configuration for a local postgres db server remains as a comment in jetty.xml, dependcies for postgres jdbc driver stay in pom.xml.