NEXUS-5472: Events not propagating

Local status and proxy mode related events were not
getting to WL manager, as event dispatcher did prematurely
some checks (that were wrong and redundant).

Also, some slight method naming fix.
NEXUS-5472: Auto blocked proxies should become "frozen"

WL should not be removed nor update tried.
NEXUS-5472: UT verifying LocalStatus and WL interaction
NEXUS-5472: UT verifying proxy mode and WL interaction
NEXUS-5587: dot file filtering for S3 scraper

With UT. The S3 that is very much different from other
scrapers were missing filtering for dot files.

By simply adding a dot entry into UT, this added
coverage.
NEXUS-5589: HTTPD scraper "un-tighten"

The Apache httpd scraper was looking for address
element as mandatory requirement. This is wrong
as it depends on server configuration, looking
and checking it only if present, but it's non
presence does not affect final decision. If present
but have unexpected value, it will prevent scraping.
NEXUS-5591: Local mode and proxy mode handling corrected

Initially these two modes of a repo (and proxy repo) were
mishandled. This change now implements proper handling of
those and extends tests covering it.
NEXUS-5472: Kill pool if threads not end cleanly

Added shutdownNow call used in case of needed, when
on shutdown the running threads cannot be canceled.

In some cases, like remote HTTP request being "stuck",
like there was case on Bamboo and Codehaus snapshots
repo, where request times out (30s) or for some reason
takes 20s to execute, this might help if this
happens during shutdown (which is often in our ITs)
NEXUS-5472: Working on remaining 0.04184

Changes:
* removed declared but never thrown exceptions from WLManager#initializeWhitelist
* update and log cleanup of EventDispatcher
* removal of redundant method from WLManagerImpl
* building better world (for devs)
* targeting west coast without dots
NEXUS-5472: Removed redundant log
Lessen debug smog.
NEXUS-5472: WL IT helper plugin and client.

This was needed, as existing "wait for" solution was very unreliable, as
it was detecting only "transitions", but that proved not enough for
recent proxyMode changes.

Now, IT helper plugin exposes same method used by UT to "wait for
bg wl jobs", and client implemented using this new resource.
NEXUS-5472: ITs redirected to new resource and cluiebt
Missing license hdr
Merge remote-tracking branch 'origin/master' into nexus-5472-fixes-wip
Merge pull request #765 from sonatype/nexus-5472-fixes-wip

NEXUS-5472: Cumulative WL fixes