[WifiCandidates] Functional equivalent for LAST_SELECTION_AWARD

Provide a way for a CandidateScorer to emulate the boost that the
SavedNetworkEvaluator gives to a network that was recently selected
by the user or by an application.

Bug: 124023173
Test: atest FrameworksWifiTests
Change-Id: I3886343489e7709ab74d6799ec0250878fcff523
5 files changed