Rewrite deploy.sh to Ruby

[asbjornu]

The deploy.sh script is becoming quite fat and since our container already has Ruby bundled, it would be better if the script was written in Ruby. Having the script in Ruby over Bash is better just in and of itself, but having it in Ruby would also allow us to add simple and fast RSpec tests for it instead of having to run the container for every little thing.

[asbjornu]

Seems like we have a few options to choose from:

• jirutka/rake-jekyll
• avillafiorita/jekyll-rakefile

Then we have ready GitHub Actions that aren't necessarily written in Ruby, but may still support what we need so we don't have to write and test it ourselves:

• Jekyll Actions
• jekyll-deploy-gh-pages
• Build & Deploy with Jekyll

I'm a bit torn. None existing solutions seems to fit the bill perfectly. The Rake tasks are outdated and tailored towards Travis. Perhaps we could fork one of them?

The GitHub Actions don't really help us in any way, since they are written in Bash, only the first one have tests and I think we would need to fork or pull-request them to support our needs.

[asbjornu]

I just discovered GitHub Pages Action that is written in TypeScript and seems very full-featured.

[NullableInt]

I just discovered GitHub Pages Action that is written in TypeScript and seems very full-featured.

Nice find!