[WIP] Rebuild website using Next.js

[samajammin]

WIP, do not merge!

Scaffolding for a new RIG website, largely based off https://github.com/ethereum/cryptography-research-website

Disclaimer: this is just an exploration... this may not be the approach we want to take.

Preview deploy

https://ef-rig.netlify.app/

Instructions for development

From the project root...

1. Install dependencies

yarn

2. Run the development server

yarn dev

3. Open http://localhost:3000 with your browser to see the result.

TODOs

• explore approach where we could use markdown for all pages (currently all subpages except for /blog & /bounties subpages)
• explore using MDX to avoid the need for custom components for each page (e.g. the /bounties subpages each have React components in addition to the markdown files - this seems highly suboptimal)

[samajammin]

@nhsz not urgent (I know you're busy with the new Geth site) but when time allows, I'd be curious to hear your take on approach here. See the TODOs in the PR description. I'm wondering if there'd be a better approach vs. copying the crypto site for enabling an easier approach to create markdown files that power new page content.