[WEB-3364] Storybook migration: remove Rails, setup GH Pages deployment

[jamiehenson]

Jira Ticket Link / Motivation

This PR is 4 of 6 when it comes to the Storybook migration. With #302, we now have a functioning Storybook integration for our Ably UI assets. This PR is all about gutting out all the old Rails assets that are no longer used, and providing a cleaner way of deploying the new assets - in this case, using Github Actions to deploy the static Storybook site to Github Pages.

Jira link: https://ably.atlassian.net/browse/WEB-3364

After this is a TSX rewrite of the Ably UI JSX components, and an investigation into swapping out Webpack as the build tool in favour of Vite.

Summary of changes

• Deployment path to GitHub Pages added to GitHub actions, which triggers on release
• Linting/formatting checks moved to GitHub Actions
• CircleCi config stubbed to run with a noop, to satisfy checks until it can be disabled for this repo
• Rails preview folder removed
• All references to Rails/Ruby processes, and Ruby assets removed

How do you manually test this?

Pull it down, get the latest packages, make sure Storybook still runs. Upon release, we'll see whether the deployment works correctly (note: I tested this exact deployment on branch push, and it worked - deploying successfully to https://ably.github.io/ably-ui.

Reviewer Tasks (optional)

Merge/Deploy Checklist

• Written automated tests for implemented features/fixed bugs
• Rebased and squashed commits
• Commits have clear descriptions of their changes
• Checked for any performance regressions

Frontend Checklist

• No frontend changes in this PR
• Added before/after screenshots for changes
• Tested on different platforms/browsers with Browserstack
• Compared with the initial design / our brand guidelines
• Checked the code for accessibility issues (VoiceOver User Guide)?

[jamiehenson]

All changes here due to linting requirements

[jamiehenson]

All changes here due to linting requirements

[jamiehenson]

All changes here due to linting requirements

[jamiehenson]

What I have here works and I feel I've chopped as deeply as I'm able to, but given that the criteria I have visibility over is mainly "does Storybook still work", I need some guidance on what happens regarding package deployment @kennethkalmer. I think this should work as I've not fundamentally touched anything there, but so much has been knifed I'm not 100%.

[kennethkalmer]

Looks great @jamiehenson! well done on being well on your way to having a total net-negative contribution 🤣🎖️

[kennethkalmer]

We won't need the subdir buildpack either since this was how we deployed preview on Heroku review apps I see storybook outputs to preview

[aleksandar-r]

Amazing work @jamiehenson, truly remarkable