devcontainer: inital config

This adds a devcontainer config for devs to have an easy way to get a working dev environment.

.devcontainer/devcontainer.json

@@ -0,0 +1,33 @@
+// For format details, see https://aka.ms/devcontainer.json. For config options, see the
+// README at: https://github.com/devcontainers/templates/tree/main/src/typescript-node
+{
+    "name": "Pybricks Code",
+    // Or use a Dockerfile or Docker Compose file. More info: https://containers.dev/guide/dockerfile
+    "build": {
+        // Path is relative to the devcontainer.json file.
+        "dockerfile": "Dockerfile"
+    },
+
+    // Features to add to the dev container. More info: https://containers.dev/features.
+    // "features": {},
+
+    // Use 'forwardPorts' to make a list of ports inside the container available locally.
+    // "forwardPorts": [],
+
+    // Use 'postCreateCommand' to run commands after the container is created.
+    "postCreateCommand": "yarn",
+
+    // Configure tool-specific properties.
+    "customizations": {
+        "vscode": {
+            "extensions": [
+                "dbaeumer.vscode-eslint",
+                "esbenp.prettier-vscode",
+                "psioniq.psi-header"
+            ]
+        }
+    }
+
+    // Uncomment to connect as root instead. More info: https://aka.ms/dev-containers-non-root.
+    // "remoteUser": "root"
+}