Automate the release process

[Tyriar]

I want to be able to queue a build on Pipelines and for it to build, publish to npm and update the website.

• Release beta builds in CI Setup continuous deployment beta builds #1872
• Make it convenient to publish a new version via Pipelines
• Automatically update the website Automatically update the website on a major/minor release #2452
• Automatically release stable versions of addons that changed Automating addon releases during xterm release #2411