main,log: parse the log related kernel command line parameters at one place only...

main,log: parse the log related kernel command line parameters at one place only, and for all tools

Previously, we ended up parsing some of them three times: in main.c when
processing the kernel cmdline, in main.c when processing the process
cmdline (only for containers), and in log.c again.

Let's streamline this, and only parse them in log.c

In PID 1 also make sure we parse "quiet" first, and then override this
with the more specific checks in log.c