replace Jekyll with a Node server 🐢🚀

[zeke]

🚧 DO NOT MERGE 🚧

This PR replaces Jekyll with a Node server using Express.

Changes to this branch are auto-deployed to electronjs.org.

Reasons™

• Developer Experience. It should be fun and easy to work on the site, and Jekyll is not always up to that task. See How can we improve Jekyll performance and usability? #668
• Consistency in Tooling. Nearly every project that the Electron team works on is written in JavaScript, and it is our language/ecosystem of expertise. Eliminating the Ruby dependency will make it easier for team members to work on the app, make more opportunities for code sharing across projects, and lower the barrier to entry for outside contributors from the community.
• Server-y Things. Using a web server will allow us to do things that a static site can't, like setting proper redirects for deprecated URLs or conditionally displaying content based on a browser's Accept-Language header. See Phasing out redirects for old docs URLs #638
• Internationalization. Eventually we'll be serving up content in different languages from electron-i18n. This will require a level of performance and flexibility that simply isn't possible with Jekyll.
• Flexibility. As the site grows and improves, we want to have the option to support things like dynamic routes, forms that users can fill out, etc.

Highlights

🌍 Localized Content - automated flow in and out of Crowdin means docs in any language!

📖 Updated Documentation - always fresh from the master branch.

💻 Apps - now categorized and each app has its own URL.

🔧 Consistent Tooling - goodbye ruby; node is everywhere.

🛰 Dynamism. running a webserver gives us dynamic routes, forms that users can fill out, etc.

🤖 Automated Deployment - greenkeeper and semantic-release ftw

Progress

See the project board.

[zeke]

I'm going to close this, as this PR is never actually going to land on the gh-pages branch. Also we've already made neo the (temporary) default branch, so any new PRs will use it as the target. I'll post a link to the blog post when the new site officially drops.

[zeke]

It's live: https://electronjs.org/blog/new-website