update favicon.ico, index.html and manifest.json

[SergiuB]

These came from CRA, need to be customized Code for Romania.

[millerrach]

Would you like an updated favicon to look like this?

[aniri]

@millerrach It looks great! We don't have one made specifically for this project, not yet. So this one seems perfect! Thanks!

[millerrach]

Great, I'll create a pull request shortly. Thanks :)