✨ Icon Picker - Convert to an NPM Package

CC: @bradystroud, @adamcogan, @wicksipedia, @isaaclombardssw

Is your feature request related to a problem? Please describe.
We've developed an icon picker that can be used in the Tina editor to add icons easily using React Icons. However, the component isn't current reusable for other Tina users.

Figure: Icon picker for website

Describe the solution you'd like
We'd like to extract the icon picker out of the website repo and create an NPM package for it. This would allow other Tina users to add icons to their site

Additional context

• Important: The icon picker currently imports the entire BoxIcons library for React. This increases our bundle size (We noticed an increase of ~700kib on the home page from using it.
• The page should work with React but be framework independent (i.e. it should work with vanilla React but have 'use client' imported at the top to ensure compatibility with Next js)
• Consider using a framework-independent code splitting method to gradually load the icons https://legacy.reactjs.org/docs/code-splitting.html

Start by locating the existing icon picker in the website repository and reviewing how it imports React Icons and the BoxIcons library. Done means the picker is extracted as an NPM package, works with React and Next.js, and avoids importing the entire icon library where possible.