Add flake8 test for vcs.

[alliepiper]

The test currently fails. The code needs to be cleaned up before merging.

@doutriaux1 @aashish24

[doutriaux1]

@aashish24 @dlonie @sankhesh this one is finally ready!
Let's merge as soon as possible to avoid too many merge conflicts in the future.

[doutriaux1]

Mac dashboard: https://open.cdash.org/viewTest.php?onlypassed&buildid=3907770

[doutriaux1]

Ubuntu dashboard: https://open.cdash.org/viewTest.php?onlypassed&buildid=3907746

[doutriaux1]

@aashish24 pinging you on this.

[aashish24]

@doutriaux1 will review it today.

[aashish24]

@doutriaux1 this is good stuff. Thanks for doing this. Minor suggestion: Commit messages could be improved for example "moving along". You can squash these commit messages into some more meaningful so that we can have a good code history. I understand that these messages are typically created during the developement.

[doutriaux1]

@aashish24 you're right, I really need to get going with the squash thing before submitting PRs. Thanks for the merge!

[aashish24]

You are welcome my friend. Squash is really useful 😄