Move notification listener management into helper.

Part of a larger effort to reuse service management code.  This is
mostly algebraic, simply move code related to listener management
into a new helper, and cut the backreference to NoMan.  Put
user-profile code into reusable inner helper, and common uid-checking
code into a new static util helper.

Resist the urge to rewrite / reformat, but replace HashSet with
ArraySet.

Bug:13743109
Change-Id: I59e0131f632c3bbf555b5276dc5092422113cdc3