Options file equivalents for command line flags

[johnomotani]

There are command line flags like --verbose and --quiet that it might be nice to be able to set in a BOUT.inp file as an alternative. I don't think this is possible currently? For example, maybe passing --verbose could set a top-level option verbose=1, or -v -v -v could set verbose=3, and then the option could also be specified in a BOUT.inp. The option would then be used to set the actual verbosity.

[ZedThree]

This should be fairly easy I think. In #2210 I change the command line parsing to convert -d into datadir= and so on, and the same machinery could be used to convert the verbosity arguments too.