Add the ability to create a folder

[jacob-macleod]

Make the New Folder button on the /flashcards page functional, by making it actually add a folder. This involves writing the python backend to facilitate this, adding any animations, including loading icons, and making the page work on mobile. You should follow the UI designs.

If you're interested at all, please reply, and I'll send through more detailed information, including the UI designs

[jacob-macleod]

I'll begin working on this

[jacob-macleod]

Created the API endpoint, but I need to add unit tests and see what happens when you mess up the folder path, like adding "///dsdj//" and things

[jacob-macleod]

~I broke the unit tests, so they need to be fixed. Also, the pipeline doesn't fail if the unit tests fail - this needs to be resolved~

[jacob-macleod]

This is now finished