Fix default population of wifi settings

Various wifi settings that are explicitly defaulted did not get their
default code properly converted to refer to the correct settings
database table.

A collection of moved-to-Global settings that had not yet been
marked @deprecated in the Secure.* namespace are now so marked.

Also updated the namespace used to refer to wifi settings from the
Wifi Service.  These changes are cosmetic, but they do eliminate a
number of runtime log messages.

Bug 7153671

Change-Id: I9e5b6464d025cfb480ef97373996e38e82f90593