Redesign site with solution that uses Markdown for content

[colinkiama]

Time for Zola to make a comeback.

Problems with current sphinx solution:

• Python may be installed but you need to install python pip
• pip doesn't let you install dependencies globally without an override flag now
• No built-in live server solution for rapid development. Contributors have to use their own solution
• reStructuredText is complex compared to Markdown. For a project that we need to rely on external contributors for content, we should be using the more simpler markup solution
• Sphinx takes a while to generate the website

How New Solution Will Be Implemented:

• Existing content can be converted to markdown using Pandoc
• Sphinx/rST-specific features can be added using Zola Shortcodes
• Will deploy the Zola version of the website on https://docs-next.vala.dev
• The Zola version of the website will replace the existing sphinx one on https://docs.vala.dev