Added Abseil log file parsing.
Added Abseil log file parsing.

This separates the severity, timestamp and source from the actual log
message and ensure that log messages are sent to the Log Explorer with
the correct severity being set.

Change-Id: I7934983d76a7b31f0be73ad3e1c6d13734342644
GitOrigin-RevId: 39464380cab639c24df7c30f78036f1b7ffef4b2

googlecloudrobotics/core,googlecloudrobotics/core,googlecloudrobotics/core