more work on idp-distribution

[Tom Zeller]

I hope that idp-distribution will help us test flows via Jetty.

In time, I would like to somehow incorporate elements of Brent's
java-shib-testbed and make sure that Marvin's overlay is compatible.

For now :
 + run 'mvn package' in idp-parent to create the runnable idp distribution
 + symlink or copy
<workspace>/java-identity-provider/idp-distribution/target/idp-distribution
to /opt/idp
 + configure the Jetty host and port etc. in /opt/idp/jetty/start.d/700-shib.ini
 + run Jetty via /opt/idp/jetty/bin/jetty.sh start

There is a silly PoC flow which prints "ok" via Velocity for the
idp/profile/Status URL.

It should be straightforward to drop flows into /opt/idp/flows and
then map them to profile URLs via /opt/idp/conf/webflow-config.xml.
Velocity views are in /opt/idp/templates.

The Jetty version is 9.1.0-SNAPSHOT because it uses the new-ish
modular start.d paradigm. The idea is that if someone wants to enable
setuid, rename start.d/110-setuid.ini.disabled to
start.d/110-setuid.ini.

Lots of things are empty or missing, I know.

My assumption is that flow definition files will be committed to
<module>/src/main/resources/flows, and idp-distribution will bundle
them together, which is a TODO.