chore: Write README for tokens package

[VincentSmedinga]

Describe the pull request

What

It documents the tokens package.

Why

The fact that it was still empty appeared glaringly evident in the package.json of a consuming application (developers.amsterdam).

How

Wrote an initial version of it.

Checklist

Before submitting your pull request, please ensure you have done the following. Check each checkmark if you have done so or if it wasn't necessary:

• Add or update unit tests
• Add or update documentation
• Add or update stories
• Add or update exports in index.* files
• Start the PR title with a Conventional Commit prefix, as explained here.

Additional notes

• Provide links to any related issues or discussions.
• Add a link to the specific story in the feature branch deploy.
• Mention any areas where additional review or feedback is needed.

[alimpens]

Nice work!

[VincentSmedinga]

I’ve rewritten it quire a bit.

Note that we have a mixed audience here:

• people creating components within the design system
• people creating custom components with different tech
• people using the tokens in a Saas-like application

I don’t mention this explicitly, but I did try to address these needs while keeping things short.

[alimpens]

I’ve rewritten it quire a bit.

Note that we have a mixed audience here:

• people creating components within the design system
• people creating custom components with different tech
• people using the tokens in a Saas-like application

I don’t mention this explicitly, but I did try to address these needs while keeping things short.

The first group shouldn't really be the audience of this README, I think? That should go in CONTRIBUTING.md. This should only be for consumers.