[NEXUS-6027] remove appcontext, still some cleanup to get app booting properly again
[NEXUS-6027] simplify servlet context listeners, expose bootstrap configuration
null on destroy, more logging, drop pointless finals
Merge branch 'NEXUS-6027-simplify-jetty-integration' into NEXUS-6027-remove-appcontext
Use @Parameters instead of appcontext to get nexus properties
Need to have "nexus-app" property set, or no plugins will load.
Added warning when system plugin dir is invalid.
Add more logging in webapp bootstrap.
Re-hookup JUL configuration.
Merge branch 'NEXUS-6027-simplify-jetty-integration' into NEXUS-6027-remove-appcontext

Conflicts:
	components/nexus-bootstrap/src/main/java/org/sonatype/nexus/bootstrap/jetty/JettyServer.java
drop test for appcontext muck
drop duplicate logging of properties
simplify property/env access
bundleBasedir -> installDir
More progress, launcher is now usable by embedded booter, pending cleanup of how default configuration is created/passed
More defense against missing required properties
Dropped logging from launcher, maybe will bring it back in some limited form (or not)
Replaced Configuration with ConfigurationBuilder
Introduced TemporaryDirectory to deal with sanity
do not cache dir, always go for sanity
canonicalize tmpdir property
drop handler muck
Add ConfigurationHolder to share properties instead of public static field
fix sp
Merge branch 'NEXUS-6027-simplify-jetty-integration' into NEXUS-6027-remove-appcontext
drop servlet context log dump hack