Misc. import fixes

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• I have read the contribution guidelines.
• Unit tests have been added for any new or changed code, and the test suite passes. Note: Your request will likely not be merged without the appropriate tests.
• "closes #XXXX" is in the body of the MR description to link the related issue, if applicable.

Make sure the kimpy modules can be at least imported without a real installation of kimpy.

Also, fix a circular import that would sometimes trigger an error.