Exit with error when bitops.config.yaml not found

[arm4b]

Fixes #310

[PhillypHenning]

This is great, thank you for doing this so quickly.
Is it worth moving the description to the doc lookup file?

[arm4b]

@PhillypHenning I think the lookup thing is outside of this PR scope as we want a fix which stops the code execution early in case of no config file provided.

If we want to switch into docs lookup way, we need to create a dedicated PR to go through all the errors, move them into lookup json and integrate into the docs so it works as one complete feature. Before the docs integration there's no value as it's harder to navigate the actual error from the code.