Switch most remaining extensions to use esbuild

Just 3 left:

- git and github. These are doing weird stuff with d.ts imports and const enums

- github-authentication  which has some tricky path mapping stuff

extensions/ipynb/esbuild.browser.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', 'browser');
+
+run({
+	platform: 'browser',
+	entryPoints: {
+		'ipynbMain.browser': path.join(srcDir, 'ipynbMain.browser.ts'),
+		'notebookSerializerWorker': path.join(srcDir, 'notebookSerializerWorker.web.ts'),
+	},
+	srcDir,
+	outdir: outDir,
+}, process.argv);