Add some VS Code / Devcontainer hints

.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",
+	// Or use a Dockerfile or Docker Compose file. More info: https://containers.dev/guide/dockerfile
+	"image": "mcr.microsoft.com/devcontainers/java:1-17-bullseye",
+
+	"features": {
+		"ghcr.io/devcontainers/features/java:1": {
+			"version": "none",
+			"installMaven": "false",
+			"installGradle": "false"
+		},
+		"ghcr.io/devcontainers/features/docker-in-docker:2": {
+			"moby": true,
+			"azureDnsAutoDetection": true,
+			"installDockerBuildx": true,
+			"version": "latest",
+			"dockerDashComposeVersion": "none"
+		},
+		"ghcr.io/devcontainers-contrib/features/act:1": {
+			"version": "latest"
+		},
+		"ghcr.io/devcontainers-contrib/features/yamllint:2": {
+			"version": "latest"
+		}
+	},
+
+	// Configure tool-specific properties.
+	"customizations": {
+		"vscode": {
+			"extensions": [
+				"vscjava.vscode-java-pack",
+				"vscjava.vscode-gradle",
+				"redhat.vscode-yaml"
+			]
+		}
+	},
+
+	// 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": "java -version",
+
+	// Uncomment to connect as root instead. More info: https://aka.ms/dev-containers-non-root.
+	// "remoteUser": "root"
+}

.vscode/extensions.json

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+{
+    "recommendations": [
+        "vscjava.vscode-gradle",
+        "redhat.vscode-yaml"
+    ]
+}

.vscode/settings.json

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+{
+    "java.configuration.updateBuildConfiguration": "automatic"
+}