Enable Yarn Plug'n'Play

[davidyell]

Is your feature request related to a problem? Please describe.
Modernise further with Yarn 3, by removing the need for the node_modules folder.

Describe the solution you'd like
The project should modernise to no longer rely on using node_modules. Needs to use the new Yarn pnp setup.

Additional context
More on how to setup zero installs.