Port github extension to use esbuild

Had to make same fixes as with #296355. We can't pull in const enums from a d.ts file like this

extensions/github/esbuild.mts

@@ -0,0 +1,19 @@
+/*---------------------------------------------------------------------------------------------
+ *  Copyright (c) Microsoft Corporation. All rights reserved.
+ *  Licensed under the MIT License. See License.txt in the project root for license information.
+ *--------------------------------------------------------------------------------------------*/
+import * as path from 'node:path';
+import { run } from '../esbuild-extension-common.mts';
+
+const srcDir = path.join(import.meta.dirname, 'src');
+const outDir = path.join(import.meta.dirname, 'dist');
+
+run({
+	platform: 'node',
+	format: 'esm',
+	entryPoints: {
+		'extension': path.join(srcDir, 'extension.ts'),
+	},
+	srcDir,
+	outdir: outDir,
+}, process.argv);