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>

arduino-ide-extension/src/browser/serial/monitor/serial-monitor-send-output.tsx

@@ -1,4 +1,4 @@
-import * as React from '@theia/core/shared/react';
+import React from '@theia/core/shared/react';
 import { Event } from '@theia/core/lib/common/event';
 import { DisposableCollection } from '@theia/core/lib/common/disposable';
 import { areEqual, FixedSizeList as List } from 'react-window';