Ignore scenarios in virtual envrionments

[audgirka]

Ignore scenarios in virtual environments.
This only works when repository is initialized with git otherwise just returns all scenario files.

Fixes: #3992

[ssbarnea]

Please add test(s) for it.

[cidrblock]

yeah, tests would be good here. The only way I can think of testing this would be to touch a molecule.yml file in a scenario tree in a gitignored directory and ensure it isn't found.

If you move the filtering logic into it's own function, it might be easier to monkeypatch it in a test so you can turn it on and off to do both a psitive and negative test.

[cidrblock]

after our conversation today, I think both + and - test can be added w/o the overhead of a venv. LMK if you need anything along the way.