wifi(API): New API surface for network suggestion

Allows apps to provide the platform a list of wifi network credentials
that the device is allowed to connect. Each NetworkSuggestion instance
will hold a standard WifiConfiguration object to represent network
credentials along with some other meta info that will help the platform
make good network selection decisions. NetworkConfigBuilder will be
reused for building the NetworkSuggestion objects as well.
Apps also have a mechanism to register to be awakened via PendingIntent
when the platform connects to one of their suggestions. This mechanism
will require the app to
a) Hold location permission, and
b) Registered PendingIntent should hold a foreground service (to prevent
abuse of this mechanism to bypass platform background limit checks).

Bug: 115504887
Test: Unit tests
Test: `make api-stubs-docs-update-current-api`
Change-Id: I9f5223fa45d49c22ce8f81d0ba56e5d12565381d