add dev container configuration for VS Code

.devcontainer/Dockerfile

+# See here for image contents: https://github.com/microsoft/vscode-dev-containers/tree/v0.234.0/containers/cpp/.devcontainer/base.Dockerfile
+
+# [Choice] Debian / Ubuntu version (use Debian 11, Ubuntu 18.04/22.04 on local arm64/Apple Silicon): debian-11, debian-10, ubuntu-22.04, ubuntu-20.04, ubuntu-18.04
+ARG VARIANT="bullseye"
+FROM mcr.microsoft.com/vscode/devcontainers/cpp:0-${VARIANT}
+
+# [Optional] Uncomment this section to install additional vcpkg ports.
+# RUN su vscode -c "${VCPKG_ROOT}/vcpkg install <your-port-name-here>"
+
+# [Optional] Uncomment this section to install additional packages.
+RUN apt-get update && export DEBIAN_FRONTEND=noninteractive \
+    && apt-get -y install --no-install-recommends qemu-system-x86 novnc \
+    && rm -rf /var/lib/apt/lists/*

.devcontainer/devcontainer.json

+// For format details, see https://aka.ms/devcontainer.json. For config options, see the README at:
+// https://github.com/microsoft/vscode-dev-containers/tree/v0.234.0/containers/cpp
+{
+	"name": "C++",
+	"build": {
+		"dockerfile": "Dockerfile",
+		// Update 'VARIANT' to pick an Debian / Ubuntu OS version: debian-11, debian-10, ubuntu-22.04, ubuntu-20.04, ubuntu-18.04
+		// Use Debian 11, Ubuntu 18.04 or Ubuntu 22.04 on local arm64/Apple Silicon
+		"args": { "VARIANT": "debian-11" }
+	},
+	"runArgs": ["--cap-add=SYS_PTRACE", "--security-opt", "seccomp=unconfined"],
+
+	// Set *default* container specific settings.json values on container create.
+	"settings": {},
+
+	// Add the IDs of extensions you want installed when the container is created.
+	"extensions": [
+		"ms-vscode.cpptools",
+		"ms-vscode.cmake-tools",
+		"webfreak.debug",
+		"austin.code-gnu-global"
+	],
+
+	// Use 'forwardPorts' to make a list of ports inside the container available locally.
+	"forwardPorts": [
+		6080 // web port of novnc
+	],
+
+	// Use 'postCreateCommand' to run commands after the container is created.
+	// "postCreateCommand": "gcc -v",
+	"postAttachCommand": "/usr/share/novnc/utils/launch.sh",
+
+	// Comment out to connect as root instead. More info: https://aka.ms/vscode-remote/containers/non-root.
+	"remoteUser": "vscode"
+}