chore(readme): remove build badges for release and nightly

* Clean up the README by removing outdated build badges
* Focus on essential information for users

Author: saturneric

README.md

@@ -3,8 +3,6 @@
 ![Language](https://img.shields.io/badge/language-C%2B%2B-green)
 ![License](https://img.shields.io/badge/License-GPL--3.0-orange)
 [![Codacy Badge](https://app.codacy.com/project/badge/Grade/d1750e052a85430a8f1f84e58a0fceda)](https://www.codacy.com/gh/saturneric/GpgFrontend/dashboard?utm_source=github.com&utm_medium=referral&utm_content=saturneric/GpgFrontend&utm_campaign=Badge_Grade)
-[![Build Release](https://github.com/saturneric/GpgFrontend/actions/workflows/release.yml/badge.svg?branch=main)](https://github.com/saturneric/GpgFrontend/actions/workflows/release.yml)
-[![Build Nightly](https://github.com/saturneric/GpgFrontend/actions/workflows/testing-nightly.yml/badge.svg?branch=develop)](https://github.com/saturneric/GpgFrontend/actions/workflows/testing-nightly.yml)
 [![Ask DeepWiki](https://deepwiki.com/badge.svg)](https://deepwiki.com/saturneric/GpgFrontend)
 
 A modern "Enigma" built on [GnuPG](https://www.gnupg.org/). It brings easy and