Squash-o-matic output

Changes:
* modules removed: nexus-utils, nexus-api, nexus-configuration, nexus-proxy, nexus-app, nexus-plugin-manager
* module "cleaned": nexus-configuration-model, now holds only modello models. Remains to be reusable (for some CLI tools)
* module nexus-core introduced, that is actually The Core of Nexus
UTs fixed
Removed all "perf" tests, as they made no sense.

Perftests for AttributeStorage was "perf" testing 3 implementations,
2 of them were totally unused (map one?) and irrelevant. The whole test
made no sense, as they were implemented at the time of Nx 2.0 when
we wanted to choose the tech that will supersede the XStream backed
one.

Same for LocalStorage, as the two test had no substantial difference,
and they were meant to catch attribute handling related problems, such
as slowdowns. Back then, there were no load tests, or any other kind
of real perf tests, so I removed them too.

Both set of tests were a muddy mixture of mocks, trickeries and such,
making the PITA to fix them, while again, their value is questionable.
Merge remote-tracking branch 'origin/master' into squash-o-matic-output

Conflicts:
	nexus/nexus-api/pom.xml
	nexus/nexus-app/pom.xml
	nexus/nexus-plugin-test-api/pom.xml
	nexus/nexus-utils/pom.xml
	nexus/plugins/restlet1x/nexus-restlet1x-plugin/pom.xml
Merge remote-tracking branch 'origin/master' into squash-o-matic-output
Moved new file in it's propr place
Commons IO slipped out

Chjange from master
Some ITs needs Nexus internals.

But after cleanup, the edition was not coming anymore to the IT
classpath. Explicitly adding it.
Merge branch 'master' into squash-o-matic-output
Getting rid of runtime repair.

Repair is tried only on boot, and during runtime,
if indexer problem is detected, it is simply made
inactive and is shut down.
markIndexerDead should handle IOEx

By logging, and not disturbing caller with it, as caller
called us already coz it had one.
[NEXUS-3728] use 'su -' intead of 'su -m'
[NXCM-4795] exclude .placeholder files
NEXUS-5383: Snapshot merges failure

The "to merge or not" decision was based on
metadata/versioning/snapshot/timestamp value.

This was wrong, as since model 1.1.0, the
newly added snapshotVersions element should be
always merged, while the "legacy" element
metadata/versioning/snapshot/timestamp
should be "merged" only if newer.
Make listener handling more robust

The goal is to not let broken code in one plugin stop the whole UI.
Before this change, listeners registered after a 'breaking' listener
would not be executed at all. This change allows event processing to
continue.
Fix requirejs dependencies
Add constructor that includes EventBus

Signed-off-by: Alin Dreghiciu <adreghiciu@gmail.com>
NEXUS-5383: More checks needed

After initial fix, another check is needed in operation.
Also, a smaller fix added, to not create VersionComparator
per list entry, but per operation instance.
Get rid of timeline repair.

Applied Igor's comments.
Use timestamped js/css files

A build timestamp in the actual resource path will provide better
browser cache busting.