dracut-logger: logging facility module for build- and boot-time

dracut-logger: logging facility module for build- and boot-time

It's dash compatible to be used also at boot-time. For now it's included
by dracut-functions and replaces functions: dinfo(), dwarning() and
derror(). New options are introduced: -L|--stdlog, and -q|--quiet to
control stderr verbosity. Logging to file or syslog may be controlled by
options set in config file.

Note that code is not adjusted to the meaning of the new logging
functions, yet.

Doxygen formatted documentation (as a proposal, by the way) is included
in dracut-logger.