fix package name (did not match filename)
code cleanup

Feature change / bugfix: values provided to '-D' must be comma separated now

 - separate environment variable and command line argument handling
 - convert shell-script fai-disk-info into perl code
 - feed parser slurped disk configuration instead of a filehandle
   (makes it a lot easier to test the parser)
 - use File::Simple and Log::Simple to provide common functionality