NEXUS-5639: Rename WL

UI panel mods:
* tab title renamed from "Whitelist" to "Routing"
* tab name changed from "whitelist" to "routing"
* "Force remote discovery" button renamed to "Update now"
NEXUS-5639: Cleaning log messages

In EventDispatcher
NEXUS-5639: Cleaning log messages

In WLManagerImpl
NEXUS-5639: Cleaning log messages

In AbstractMavenRepo
NEXUS-5639: "Deep" rename WL to Routing

Initial code changes, bundle smoke tested and is working.

Tests and ITs not verified yet.
NEXUS-5639: URL change of the resources

Client is handled too
NEXUS-5639: M2 repo external config change

Renamed externalConfiguration nodes too
NEXUS-5639: Rename thread names

From "wl" to "ar" as Auto routing...
Merge pull request #794 from sonatype/nexus-5639-rename-wl

[2.4 blocker] NEXUS-5639: Rename WL
Merge pull request #795 from sonatype/nexus-5639-rename-wl-deep

[blocker 2.4] NEXUS-5639: Deep rename of WL into Routing
Back to version 2.4-SNAPSHOT
NEXUS-5602: Using the periodic update thread for initial updates too

On 1st boot of updated instances, a lot of MavenRepository
instances (hosted and proxy) will be piled up in the array
needUpdateRepositories in WLManagerImpl#startup().

Currently, as the thread pool with fixed size of 5 and
blocking queue was deferring update.

With this change, the for-loop doing initial WL build
(walk of the content for hosted and discovery for proxies)
is deferred, and periodic updater thread is used.

This also means, that upon boot, the initial delay of
first run will be applied, and on that moment on, hosted
reposes will have WL, not before that.

Initial change breaks all the UTs and ITs that uses
exposed-for-tests-only method to reach a state when
the test should start.

isUpdateWhitelistJobRunning() method used for this
is now updated, and will flag (and make tests wait)
as long as boot sequence is done (newly added) AND
there are no bg updates running (as before).

Also, EventDispatcher simplified, the feature active
flag is not passed anymore, instead, it is not
registered to event bus when feature is not
active, resulting in same behavior (before, when
feature was inactive EventDispatcher got events
but simply did not invoke WL Manager).
Merge pull request #792 from sonatype/nexus-5602-using-updater-for-initial-update

REVIEW: NEXUS-5602: Using the periodic update thread for initial updates too
Fixing the build.

Prefix updates happens async on config
save, and the UT did not properly wait for
them.
Merge remote-tracking branch 'origin/master' into file-list-io-error