Set up CI and create stable branch

[miketynes]

@jschrier has indicated that we can spend our way out of the CI problem, e.g circleCI, some other provider

[vshekar]

As part of stabilizing the master branch we also need to

1. Enforce a code style guide. I nominate black to do this. Most IDEs have plugins that autoformat to the style on save
2. Logging: especially to log variables in code with frequent issues (For example robot file generation)
3. Raise exceptions where appropriate. Recent example, I showed @nsmina914 to raise one if the phase data for a chemical is missing
4. Separation of concerns. core.utilities has to be cleaned up so that functions are placed in the right place. Experiment create also does too many things and can be refactored.

Some of the above can be an issue on its own. For example I can take ownership of refactoring