Fixed the TestBench packaging for release

 - Include all relevant modules in the maven/ directory
 - Update the INSTALL file for the new modules
 - Add the manual pdf back again
 - Move manual generation from vaadin-testbench-core to vaadin-testbench
 - Add license info to vaadin-testbench/pom.xml
 - Make vaadin-testbench generate a jar good for Vaadin Directory

Change-Id: Ibbcdaea3fb2bfd34211e848872a6cd170f0b1c9a