OP-179 Refactor Form

[dominicmacaulay]

Why?

With the move towards pure css, the setup of forms needed to change.

What Changed

What changed in this PR?

• Convert form.scss to form.css using BEM
• Update the form docs

Sanity Check

• [ ] Have you updated any usage of changed tokens?
• Have you updated the docs with any component changes?
• [ ] Have you updated the dependency graph with any component changes?
• Have you run linters?
• Have you run prettier?
• Have you tried building the css?
• Have you tried building storybook?
• Do you need to update the package version?

[linear]

OP-179 Refactor Form