Feature: add form design base styles

[jonwaldstein]

Description

This loads a base css file before other form designs for an easier starting place. By utilizing pico.css & css @layers we can scaffold a classless stylesheet that form designs can easily customize with their own css.

The way we are using pico.css is by pulling in their individual source files. This gives us the flexibility of only importing what we want.

Affects

• The developer form design uses the base styles now - so all if its own styles have been removed.
• Tweaks to the classic form design & removing styles that are now apart of the baseline.
• Removes the WP global styles from our iframe views. We can revisit this when discussing fse/theme.json compatability.

Visuals

Testing Instructions

• Pull branch and npm install && npm run build
• Switch between classic and developer form designs

Pre-review Checklist

• Acceptance criteria satisfied and marked in related issue
• Relevant @unreleased tags included in DocBlocks
• Includes unit tests
• Reviewed by the designer (if follows a design)
• Self Review of code and UX completed

[jonwaldstein]

@kjohnson @JasonTheAdams this is ready for review.

[kjohnson]

This looks awesome! A class-less base styling will be a better developer experience when doing a custom design.