First run experience might be improved

[Tim Sampson]

e.g.

pi l                                                                                                                            
File "/home/tsampson/.pi.toml" could not be opened. Check that it exists.

I'm not sure what might be better here. Create one on first run? Through a wizard (if you want to go that far). Some of the values can probably be inferred from other places (.gitconfig if it exists for example, possible env vars). But maybe there's a simple way to improve this a bit too.