add devcontainer support

.devcontainer/devcontainer.json

@@ -0,0 +1,22 @@
+// For format details, see https://aka.ms/devcontainer.json. For config options, see the README at:
+// https://github.com/microsoft/vscode-dev-containers/tree/v8.0/containers/dotnet
+{
+  "name": "dotnet",
+  "image": "mcr.microsoft.com/devcontainers/base:debian",
+  "customizations": {
+    "vscode": {
+      "extensions": [
+        "ms-dotnettools.csdevkit",
+        "EditorConfig.EditorConfig",
+        "DavidAnson.vscode-markdownlint"
+      ]
+    }
+  },
+  // Use 'postCreateCommand' to run commands after the container is created.
+  "postCreateCommand": "bash -i ${containerWorkspaceFolder}/.devcontainer/scripts/post-creation.sh",
+  // Add the locally installed dotnet to the path to ensure that it is activated
+  // This is needed so that things like the C# extension can resolve the correct SDK version
+  "remoteEnv": {
+    "PATH": "${containerWorkspaceFolder}/.dotnet:${containerEnv:PATH}"
+  }
+}

.devcontainer/scripts/post-creation.sh

@@ -0,0 +1,4 @@
+# Install SDK and tool dependencies before container starts
+# Also run the full restore on the repo so that go-to definition
+# and other language features will be available in C# files
+./restore.sh