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 #795 from sonatype/nexus-5639-rename-wl-deep

[blocker 2.4] NEXUS-5639: Deep rename of WL into Routing