chore: Re-structure workspaces, enforce build order

These are some changes in the way the monorepo is structured,
that are aimed at making it easier to get started.

There are two important changes:

**Multiple workspaces**

We had a yarn workspaces setup at `packages/*`. But our monorepo has
grown to 92 packages which can be overwhelming for people not familiar
with the package names.

To remedy this, I've split it into 4 different workspaces:

- `designs/*`: Holds FreeSewing designs (think patterns)
- `plugins/*`: Holds FreeSewing plugins
- `packages/*`: Holds other packages published on NPM
- `sites/*`: Holds software that is not published as an NPM package,
  such as our various websites and backend API

This should make it easier to find things, and to answer questions like
*where do I find the code for the plugins*.

**Updated reconfigure script to handle build order**

One problem when bootstrapping the repo is inter-dependencies between
packages. For example, building a pattern will only work once
`plugin-bundle` is built. Which will only work once all plugins in the
bundle or built. And that will only work when `core` is built, and so
on.

This can be frustrating for new users as `yarn buildall` will fail.
And it gets overlooked by seasoned devs because they're likely to have
every package built in their repo so this issue doesn't concern them.

To remedy this, we now have a `config/build-order.mjs` file and the
updated `/scripts/reconfigure.mjs` script will enforce the build order
so that things *just work*.

packages/freesewing.dev/components/help-us.js

@@ -1,49 +0,0 @@
-import Popout from 'shared/components/popout.js'
-
-const HelpUs = ({ mdx=false, slug='/' }) => (
-  <details className="mt-4">
-    <summary>Click here to learn how you can help us improve this page</summary>
-    {mdx && (
-      <Popout tip className='max-w-prose'>
-        <h6>Found a mistake?</h6>
-        You can <a
-          href={`https://github.com/freesewing/freesewing/edit/develop/markdown/dev/${slug}/en.md`}
-          className="text-secondary font-bold"
-        >edit this page on Github</a> and help us improve our documentation.
-      </Popout>
-    )}
-    <Popout comment by="joost" className='max-w-prose'>
-      <h6>Does this look ok?</h6>
-      <img
-        className="my-4 rounded"
-        src={`https://canary.backend.freesewing.org/og-img/en/dev${slug}`}
-      />
-      <p>
-        If it looks ok, great! But if not, please let me know about it.
-        Either by <a href="https://discord.freesewing.org/" className="text-secondary">
-          reaching out on Discord
-        </a> or feel free to <a
-          href="https://github.com/freesewing/freesewing/issues/new/choose"
-          className="text-secondary"
-        >create
-        an issue on Github</a>.
-      </p>
-      <h6>Why do you ask?</h6>
-      <p className="text-base">
-        I recently added a backend endpoint to auto-generate pretty (I hope) Open Graph images.
-        They are those little preview images you see when you paste a link in Discord (for example).
-      </p>
-      <p className="text-base">
-        This idea is that it will auto-generate an image, but I am certain there are some edge cases
-        where that will not work.
-        There are hundreds of pages on this website and checking them all one by one is not something
-        I see myself doing. But since you are here on this page, perhaps you could see if the image
-        above looks ok.
-      </p>
-      <p className="text-base">Thank you, I really appreciate your help with this.</p>
-    </Popout>
-  </details>
-)
-
-export default HelpUs
-