Remove dead code.

Nx repo metadata api was originally using
Restlet Client as transport, but it was
reworked to use Hc4Provider since introduction
of it. This code is not used since then,
and the restlet deps are unneeded also.
These classes got duplicated by collapse

Or were duplicated before collapse? Anyway,
removed the dupes.
Not exactly a dead code but...

This IT was testing Jetty from test harness for
it's proxy servlet authentication.

Nothing to do with Nexus.

Original commit introducing it:
https://github.com/sonatype/nexus/commit/a2d34298f09b16d58a1c4cf68278ea0010839f3e
fix nexus-site-repository-plugin js load issue
missed license header and guice annotations on last commit
changing the boot path for the nexus-site-repository-plugin js
better solution than the last, add a boot js file and use require style
use TestUtil to resolve file paths, corrects for problem where IDE by default uses a different base directory for tests than expected by mvn
remove two localized duplications of code available in org.sonatype.nexus.rest.model.HtmlUnescapeStringConverter
Merge pull request #14 from sonatype/remove-dead-code

Remove dead code
Fixing parent.

As it was moved, parent was not updated.
Fixing the one method that left nx state changed.

While this is not important now, this breaks the ClientIT
when changed to JUnit 4.11 as test execution ordering
will change.
Fixing the P2 legacy IT merge.

The legacy-testsuite uses nexus-test-env-m-p that
in turn does NOT employ ArtifactHandlers to figure
out artifact properties from it's type (ie. nexus-plugin
is c:bundle and e:zip). Hence, it needs "raw" coordinates
to properly pick up the plugin it's about to install
to the Nx test subject.

plugins/pom now holds (basically duplicated) entry
for P2 plugin, but this should be sorted out by some
other means, probably by fixing n-t-e-m-p.

Verified locally, legacy ITs now executes properly,
before it was not even started due to goal
setup-enviornment failure, failing the build (as being
unable to "resolve" the p2 plugin from dependencies).
Removed unused dep
use nexus.version instead of D entry, drop groovy dep its not needed
drop DM for bundle zip
add note about unstable tests
need for pr tests, no need for calling out jira here
some more docs
use root project for docs