apps: move addNote function to logHelper

The handy addNote function is moved from the logSummary object to the
more general logHelper object.  This allows log types other than
Chrome OS and Brillo to use the functionality.

TEST=manually tested with log files for Chrome OS and Brillo

Change-Id: Ia7d3c38ac7b437e2e188f081bb9593efee24c79d
4 files changed