LPS-50105 Improve error handling in RTL generation

In order to display messages in both build-time and run-time, System.err is used instead of Log.
LPS-50049 The lines that starts with ## should be ignored, but all the lines of the file should be processed.
LPS-50049 SF
LPS-50105 We should use _log but change how we call it from the command line to ensure Log is wired. Otherwise, a portal admin could never tweak the logging level
After SF is needed change the expected result in the test