Add a workflow to build and deploy esp-hal documentation to GitHub Pages

[jessebraham]

Supersedes #1243, fair bit of progress on #1204 in the process.

In addition to the work done in #1243 (thanks @playfulFence!), I've made a number of small changes:

• We now inject the package version into the URL, so that we can host multiple versions of the docs
• Documentation deployment now happens in its own workflow
• The index.html file was formatted, and a favicon was added
• Took @igrr's advice and used the actions/upload-pages-artifact and actions/deploy-pages actions in the workflow

Right now the workflow must be dispatched manually, we can revisit this in the future. There are additionally a number of other improvements I'd like to make, but for the sake of getting this release out I'll worry about those details at a later time.

Successful workflow run: https://github.com/jessebraham/esp-hal/actions/runs/8177237322
Deployed: https://jessebraham.github.io/esp-hal/

[bjoernQ]

LGTM!

[SergioGasquez]

LGTM! Only a small question that I have.