chore(deps): Updated to Theia 1.39.0 (#2144)

- update Theia to `1.39.0`,
 - remove the application packager and fix the security vulnerabilities,
 - bundle the backed application with `webpack`, and
 - enhance the developer docs.

Co-authored-by: Akos Kitta <a.kitta@arduino.cc>
Co-authored-by: per1234 <accounts@perglass.com>

Signed-off-by: Akos Kitta <a.kitta@arduino.cc>

electron-app/webpack.dev.js

@@ -0,0 +1,22 @@
+// When running in development mode, do not webpack the backend and electron main modules.
+// It does not work in watch mode: https://github.com/eclipse-theia/theia/issues/12793.
+const path = require('node:path');
+const configs = require('./webpack.config');
+const { createCopyArduinoResourcesPlugins } = require('./webpack.base');
+const [mainWindowConfig, preloadConfig] = configs;
+
+// Use the frontend's webpack config to copy the required resources to the `./arduino-ide-extension/lib/node/resources` folder.
+mainWindowConfig.plugins?.push(
+  ...createCopyArduinoResourcesPlugins(
+    path.join(
+      __dirname,
+      '..',
+      'arduino-ide-extension',
+      'lib',
+      'node',
+      'resources'
+    )
+  )
+);
+
+module.exports = [mainWindowConfig, preloadConfig];