WifiNetworkFactory: Implement network matching using network specifier

Changes in the CL:
a) Match incoming scan results with the active network specifier.
b) Identify unique networks. Multiple BSSIDs (ScanResult) within the same
network are collapsed into one entry.
c) Send these matched networks to the registered callback to present to
the user.

Bug: 113878056
Test: Unit tests.
Change-Id: I2805c35c1378c20399890b9538cd5558f5f6d6
3 files changed