v3 idp-distribution notes

[Tom Zeller]

I have committed changes to build a minimally runnable IdPv3
distribution, here are some notes.

For now, the v3 IdP will just provide an incomplete port of the v2
StatusServlet. That servlet will live in idp-core. The web.xml in
idp-war is a mostly-commented-out port from v2, and the JSPs which
refer to v2 are obviously broken. The v3 web.xml also targets
web-app_3_0.xsd instead of 2.4.

The idp-war web.xml no longer has a contextConfigLocation param, that
param is now set by the idp.xml jetty context descriptor. This may
change.

The idp-distribution targets Jetty 9.0.3-SNAPSHOT because of the new
modular start.d ini files. The Jetty version is now defined as a
property in parent-v3/pom.xml.

I have created jetty9-dta-ssl based on jetty7-dta-ssl.

Both idp-distribution and jetty9-dta-ssl temporarily include the Jetty
snapshot repository in pom.xml, which should be removed after the next
Jetty release.

For now, idp-distribution creates the distribution in
target/idp-distribution and idp-assembly.xml just archives that
directory into a zip and tar.gz. The maven assembly descriptor is kept
as simple as possible; the logic of creating the distribution resides
in pom.xml.

It is possible to run the v2 IdP using the v3 idp-distribution and
Jetty9, just point the idp.xml context to the v2 idp.war.

As of right now, idp-distribution does not build with -Prelease, but
'mvn package' produces a runnable distribution.