Draft of a devcontainer development environment

A minimal devcontainer for building and running CRG scoreboard. Tested
with the [devcontainer CLI](https://github.com/devcontainers/cli), I
haven't tested it with VS Code yet.

Will likely want to add additional tools like language servers, etc.
to make development easier.

see https://containers.dev

.devcontainer/Dockerfile

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+FROM mcr.microsoft.com/devcontainers/java:1-21-bookworm
+
+RUN apt-get update && apt-get install -y ant

.devcontainer/devcontainer.json

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+// For format details, see https://aka.ms/devcontainer.json. For config options, see the
+// README at: https://github.com/devcontainers/templates/tree/main/src/java
+{
+	"name": "Java",
+	"build": {
+		"dockerfile": "Dockerfile"
+	},
+	// // Or use a Dockerfile or Docker Compose file. More info: https://containers.dev/guide/dockerfile
+	// "image": "mcr.microsoft.com/devcontainers/java:1-21-bookworm",
+
+	"features": {
+		"ghcr.io/devcontainers/features/java:1": {
+			"version": "none",
+			"installMaven": "false",
+			"installGradle": "false"
+		}
+	},
+
+	// Use 'forwardPorts' to make a list of ports inside the container available locally.
+	"forwardPorts": [],
+	"appPort": ["127.0.0.1:8000:8000"]
+
+	// Use 'postCreateCommand' to run commands after the container is created.
+	// "postCreateCommand": "java -version",
+
+	// Configure tool-specific properties.
+	// "customizations": {},
+
+	// Uncomment to connect as root instead. More info: https://aka.ms/dev-containers-non-root.
+	// "remoteUser": "root"
+}