chore: add VS Code Dev Container (falconry#2132)

.devcontainer/devcontainer.json

@@ -0,0 +1,24 @@
+// 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",
+	"image": "mcr.microsoft.com/devcontainers/python:3.11",
+	"features": {
+		"ghcr.io/devcontainers-contrib/features/tox:1": {}
+	}
+
+	// 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": "pip3 install --user -r requirements.txt",
+
+	// Configure tool-specific properties.
+	// "customizations": {},
+
+	// Uncomment to connect as root instead. More info: https://aka.ms/dev-containers-non-root.
+	// "remoteUser": "root"
+}

CONTRIBUTING.md

@@ -133,6 +133,10 @@ $ gnome-open docs/_build/html/index.html
 $ xdg-open docs/_build/html/index.html
 ```
 
+### VS Code Dev Container development environment
+
+When opening the project using the [VS Code](https://code.visualstudio.com/) IDE, if you have [Docker](https://www.docker.com/) (or some drop-in replacement such as [Podman](https://podman.io/) or [Colima](https://github.com/abiosoft/colima) or [Rancher Desktop](https://rancherdesktop.io/)) installed, you can leverage the [Dev Containers](https://code.visualstudio.com/docs/devcontainers/containers) feature to start a container in the background with all the dependencies required to test and debug the Falcon code. VS Code integrates with the Dev Container seamlessly, which can be configured via [devcontainer.json](.devcontainer/devcontainer.json). Once you open the project in VS Code, you can execute the "Reopen in Container" command to start the Dev Container which will run the headless VS Code Server process that the local VS Code app will connect to via a [published port](https://docs.docker.com/config/containers/container-networking/#published-ports).
+
 ### Code style rules
 
 * Docstrings are required for classes, attributes, methods, and functions. Follow the