Changed Launch Icon and app name

[Yaswanth-Mitta]

🎯 Add an icon to the app. #13

I sucessfully changed App Icon and App name and whie trying to remove native default splash screen I came to know that it is not possible in some versions of flutter we can only remove the icon with android native java code which is not preferred. The time it takes to show default native splash screen is the time taken by os to run the application so It is preferred not to customize it .

Also fixed the issue while running the app in some versions of flutter which is caused by url launcher package

Closes #13

🗒️ Checklist:

• I have mentioned the issue number in my Pull Request.
• I have gone through rules of when PR will get merged.
• I have commented my code, particularly in hard-to-understand areas
• I have created a helpful and easy to understand README.md
• I have followed proper file structure.
• I have gone through CONTRIBUTING GUIDELINES.md.

---

Add your screenshots(Optional) 📸

DU.Hacks.mp4

---

Thank you for contributing!❤️

Don't forget to show some love by ⭐ the repository!