logging: syst: embed log message source IDs in Sys-T messages

This embeds the log message source IDs inside the origin unit
as module IDs in Sys-T messages. This allows Sys-T message
parsers to see where the log messages are coming from.

This is enabled by default if using Sys-T catalog messages as
the collateral XML file contains the information to interpret
the module ID.

Signed-off-by: Daniel Leung <daniel.leung@intel.com>