Local fonts section implementation in React

[matiasbenedetto]

What?

In this PR:

• Implement the local font asset upload in the React App
• Add variable fonts preview capabilities
• Add variable wieght font logic to build the theme.json (doesn't add fontWeight property if the fonts has a a wghtvariable axis.
• Change the styles of this section to make it look as the rest of the font section as implemented in Fonts outline sidebar #260

Why?

To allow us to implement the user ability to add more configuration options.

How to test:

For classic fonts:

• Go to the "Add local font" page
• Add a few fonts a test if everything is working as before.

For variable fonts:

• Go to the "Add local font" page
• Upload a variable font (preferably one that implements the wght variable axis).
• Try the variable font preview options
• Upload the font

[jffng]

My comments are mostly UI related but it's mostly working as expected, thanks!

Change the styles of this section to make it look as the rest of the font section as implemented in #260

So on PR 260 I see this is what adding a Google Font looks like:

On this PR, the local fonts page looks like this:

Should we aim to bring these closer together in this PR? For example, the padding and the layout are different. I think the initial state looks a bit "broken" until you load a font because there is no indication that the right column is reserved for the font preview:

[matiasbenedetto]

I think the initial state looks a bit "broken" until you load a font because there is no indication that the right column is reserved for the font preview

Good point, I added a message for the initial state.

When a variable font is loaded it looks like this now:

[jffng]

Nice improvements, thanks! I think it's in a spot we can merge and iterate. Pre-approving with a couple notes:

1. Let's try and bring the Google Fonts and Local Fonts layout closer together in a follow up.
2. I noticed a security warning when I ran npm install. So maybe running npm audit and fixing the package vulnerabilities would be of good conscience.