Poetry migrate

[pchlap]

With poetry 1.2 to be released soon, preparing to migrate platipy to manage dependencies using poetry.

[pchlap]

• [x] Error message when running cardiac and not VTK
• [x] Ensure logging still works properly for backend code
• [ ] Github action to deploy to pypi
• [x] Check some dependency constraints and consider loosening

[pchlap]

Hi @rnfinnegan, this is just about ready to go. Could you leave an approval if you're happy? Thanks :)