Monitor station events for hotspot mode

This enables NetlinkManager to monitor NL80211_CMD_NEW_STATION,
and NL80211_CMD_DEL_STATION.

This could be used for ApInterfaceImpl for monitoring associated
stations.

This also creates a new class LoggingUtils to avoid repeating code.
This also adds corresponding unit tests.

Bug: 36043922
Test: compile, unit tests, manual tests

Change-Id: I060062c0cd6250051da90658b229d786f287fad4
12 files changed