ref flake instrumentation into adapter IV/V

[blaggacao]

This PR is built cumulatively on top of
three other PRs.

For confidence in review, only the fourth
commit is meant to be considered.

• Refactor data to settings (specificity)
• Refactor data structures into their own module
• Refactor implement from_str trait for Target data
• Refactor move flake parsing into adapter file

By moving the flake adapter into it's own module,
we make future implementations of a different
data source at least more obvious.

Since this tool has become a lib, we might seem
implementations in this field.