apps: add supplicant state transitions to viz

Display logged supplicant state transitions as an additional graph
in the manager visualization section of the log processor.  A line will
not be plotted in the new graph if the ssupplicant state transitions are
not logged.  Added tests to verify supplicant state transition entries.

BUG=chromium:466262
TEST=manually tested and ran 'grunt test'

Change-Id: Ibc306f24d069b097ce712bf73e1e154957aa56cf
6 files changed