Allow --prefer,--ignore,--avoid to filter on /proc/procid/cmdline

[feberbo]

When running a python main program that spawns other python process (like Airflow) I would like to be able to filter on the cmdline of the process, because they are all python processes but have differing cmdlines which would allow me to do a better selection.

[hakavlad]

github.com/hakavlad/nohang supports it