Document config options

[amorison]

Configuration options should be documented on the online documentation. Helpers could be provided from the command line as well, using the help_string metadata linked to every option in config.py.

[amorison]

Command line helpers are now available with merge 85e3c89.

[amorison]

Automatic generation of a list of configuration options is done with commit 40bfa0a.

This can be further improved in the future of course, but I'll close this issue now.

Here is what it looks like

https://stagpy.readthedocs.io/en/latest/sources/config_opts.html