Downgradle libpam4j to work around error in JNA:

JNA 3.3.0 and later can fail with "GLIBC_2.11 not found" message

JNA 3.2.2 works.
Simple abstract base module
Abstract base module for supporting chained auth mechanisms
Move Jetty specific code to support class
Refactor to use base modules
Add property file based modules to enhance jetty's property file module
Improve debug output, and cleanup