Add ciffile dependency

[tacaswell]

Does two things:

• do not check into git or track git_verinfo.py as soon as you commit it, it is wrong!
• adds pycifrw to pyproject.toml

[briantoby]

I'll take a look at this PR when I get a chance.

I can see that I'm using git_verinfo.py for multiple roles that I probably need to be split up. I'll have to think about that more.

[briantoby]

• fixed the dual use of git_verinfo.py by creating an untracked file (not yet used)
• cleaned up self tests
• copy exe's for pixi install-editable (unix only)