NEXUS-5472: Getting rid of a potential bottleneck

The offer/revoke entries are invoked per every content
change (deploy, delete), but the WL will rarely change
(only when new top level prefix is deployed or removed).
Hence, the heavy handed exclusive lock is reworked into
DCL-like solution, with premise that "more work at less
occasions" is better than serializing deploys.
NEXUS-5462: Leftover when varargs removed: plural

Method name made singular.