Implement no-circular-imports

[illright]

This should probably be implemented outside of the FSD plugin, since it's not exclusive to FSD. I'm not sure if it's best to create another native plugin or have this rule in "Steiger core"

The idea of this rule is simple — prevent circular imports (when A imports from B, but B imports from A, or maybe A -> B -> C -> ... -> A).

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For simplicity, let's put this rule to the FSD plugin for now, and if there will be more generic rules like this, then we'll think about moving them out into a separate plugin

[illright]

We might be able to learn from this project — https://github.com/antoine-coulon/skott