Add minimal dev container configuration

We would probably want something more fully featured than this, but this
is a start with VSCode's configuration tool, and some manually added
extensions.

For more, we could use a Dockerfile or Docker Compose file that we
provide.

.devcontainer/devcontainer.json

@@ -0,0 +1,48 @@
+// For format details, see https://aka.ms/devcontainer.json. For config options, see the
+// README at: https://github.com/devcontainers/templates/tree/main/src/python
+{
+	"name": "Python 3",
+	// Or use a Dockerfile or Docker Compose file. More info: https://containers.dev/guide/dockerfile
+	// 2023-06-29: Use bullseye image instead of bookworm.
+	// At time of writing, bookworm is new and may have issues with dev containers:
+	// https://github.com/devcontainers/features/issues/576
+	"image": "mcr.microsoft.com/devcontainers/python:3.11-bullseye",
+
+	// Features to add to the dev container. More info: https://containers.dev/features.
+	"features": {
+		// TODO: Not sure if we would be better installing tools via requirements.txt.
+		"ghcr.io/devcontainers/features/python:1": {
+			"installTools": true,
+			"installJupyterlab": true,
+			// https://github.com/devcontainers/features/issues/598#issuecomment-1612216163
+			"version": "none"
+		},
+		"ghcr.io/devcontainers/features/docker-in-docker:2": {
+			"moby": true,
+			"azureDnsAutoDetection": true,
+			"installDockerBuildx": true,
+			"version": "latest",
+			"dockerDashComposeVersion": "v2"
+		}
+	},
+
+	// 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": "pip3 install --user -r requirements.txt",
+
+	// Configure tool-specific properties.
+	"customizations": {
+		"vscode": {
+			"extensions": [
+				"ms-python.python",
+				"ms-toolsai.jupyter",
+				"ms-toolsai.jupyter-renderers"
+			]
+		}
+	}
+
+	// Uncomment to connect as root instead. More info: https://aka.ms/dev-containers-non-root.
+	// "remoteUser": "root"
+}