Swift: add devcontainer setup

.devcontainer/swift/devcontainer.json

@@ -0,0 +1,28 @@
+{
+	"extensions": [
+		"github.vscode-codeql",
+		"hbenl.vscode-test-explorer",
+		"ms-vscode.test-adapter-converter",
+		"slevesque.vscode-zipexplorer",
+		"ms-vscode.cpptools"
+	],
+	"settings": {
+		"files.watcherExclude": {
+			"**/target/**": true
+		},
+		"codeQL.runningQueries.memory": 2048
+	},
+	"build": {
+		"dockerfile": "Dockerfile",
+		"args": {
+			"VARIANT": "ubuntu-20.04"
+		}
+	},
+	"runArgs": [
+		"--cap-add=SYS_PTRACE",
+		"--security-opt",
+		"seccomp=unconfined"
+	],
+	"remoteUser": "vscode",
+	"onCreateCommand": ".devcontainer/swift/user.sh"
+}