chore: create devcontainer for GitHub Codespaces

[HonkingGoose]

Changes:

• Create .devcontainer file with GitHub Codespaces setup
• Use Node 22 as basis for the container image

Context:

With my changes you can:

• Create a development enviroment by clicking on the green <> Code button on any branch of your repository (this also works on forks that have pulled in this change)
• You can use the browser to work on your change, and see the preview of the live site
• You do not need to worry about installing the right dependencies

You will need to update the "image": "mcr.microsoft.com/devcontainers/javascript-node:1-22-bookworm", part from time to time. GitHub added a Dependabot config during the setup steps for the Node.js container.

I recommend using a bot to update the container file regularly. It's easy to forget. 😄

Docs

• GitHub Docs, GitHub Codespaces overview
• GitHub Docs, Working in a Codespace in the browser