Health: experiment to add Knip to the local toolchain

[KaliedaRik]

This PR is an experiment to see if we can use a new tool - Knip - to help us manage JS/TS dependencies more effectively across this repo.

Trello ticket: https://trello.com/c/SVNb7chp

Actions taken which have resulted in this PR:

• Add Knip to the repo root as a dev dependency
• Run yarn knip to generate an initial report of issues across the repo
• Run yarn knip --fix-type dependencies to attempt to fix the identified dependencies across all package.json files within the repo.

Testing

TODO: devise a way to test these updates, both locally and in CODE

[KaliedaRik]

Closing as this was just an experiment