chore: Add dev container

[LewisHogan]

Description

Add a .devcontainer configuration so that contributors with a container runtime (e.g. docker) do not need to setup a development environment.

When testing on my m1 macbook air I needed to ensure that the container runtime had at least 4GB available in order to get the build:test script to run, but the preview and the build script both ran without any changes and I suspect that's a consequence of my particular setup.

Checklist:

• [x] I have read and followed the requirements in the Contributing document.
• [x] My code has been tested.
• [x] My commit title follows Conventional Commits formatting.
• [x] All the code is my own, or is code I have the rights to, and is being made available under the Apache License Version 2.0.