Add --log-level support - Issue #5198

I noticed that even if I set the log level to 'fatal' there are still quite a few things printed to stdout/err.
In my quick scan its because not everything is using the default logger.  For example, I noticed that
job.go has its own.  I think that should be removed and everyone should use the same logger.
I could move that change into this PR if people want, but I'd prefer to split it out into a new one so that
this one is just focused on adding the --log-level flag.

Closes #5198

Signed-off-by: Doug Davis <dug@us.ibm.com>
working backwards....  I wouldn't want to skip all of this because if they give a bad log-level then I think we should flag it even if -D was specified.  To the point that nothing is more verbose than Debug, true right now and I can change it but the way its currently coded, if some other level does pop up that's more verbose (as part of logrus) then it won't break us and it'll just work.  If you feel strongly I can hard code the assumption that "debug" is always the most verbose - just let me know.