Replatform to make local build and updates possible

[LL782]

Why

1. The site was built with Gatsby and has fallen badly out of date
2. Local build is not possible
3. Remote build and deployment is failing too, if I recall correctly

What

• Draft a plan for re-platforming
• Plan first steps
• Get started replatforming

Notes

1. This is a good opportunity to research the latest good, stable options for a CMS
2. Maybe a good opportunity to do a headless, self-hosted Wordpress
3. Favour a quick and easy solution that still gives me flexibility