feat: add devcontainer.json

[DavidDeSloovere]

Description

This allows developers on Windows to open the project in VS Code using a Docker container that runs Debian, including Node, Deno, Bun.

vscode ➜ /workspaces/h3 $ bun --version
1.0.16
vscode ➜ /workspaces/h3 $ node --version
v20.10.0
vscode ➜ /workspaces/h3 $ deno --version
deno 1.38.5 (release, x86_64-unknown-linux-gnu)
v8 12.0.267.1
typescript 5.2.2

Is able to run the tests without issues using npm run test

Linked Issues

#25

Additional context

All files where 'changed' in git, because I first opened in Windows before creating the devcontainer. Adding extra config to .gitattributes to specify line endings.

[kazupon]

Thank you so much!
LGTM!