Create Serbian README

[nemanya-d]

What is it?

• Bugfix (user facing)
• Feature (user facing)
• Codebase improvement (dev facing)
• Meta improvement to the project (dev facing)

Description of the changes in your PR

Added translation of the README into Serbian.

Due diligence

• I read the contribution guidelines.

[TobiGr]

Thank you.
Link the Serbian file in the other translated READMEs, too please.

[nemanya-d]

Thank you. Link the Serbian file in the other translated READMEs, too please.

You're welcome!

Note: I needed to make a separate commit for the all READMEs, I'm not that experienced on GitHub haha.

[TobiGr]

Thanks, We will take care of the commits later when merging this PR. Many images have relative URLs which need to be fixed.

[nemanya-d]

Thanks, We will take care of the commits later when merging this PR. Many images have relative URLs which need to be fixed.

Done. Thanks for the help!

[TobiGr]

thanks!

[nemanya-d]

thanks!

Hey, I just noticed that I didn't fix URLs for images in the "Donate" section. Forgot to replace with ../assets/. Fix that please, if that's possible

[TobiGr]

done

[nemanya-d]

done

That was fast, thank you!

Unrelated to this PR

I noticed that there is no Russian translation of the README linked in any of the READMEs, I don't know if there is a reason for that, but I just wanted to let you know that.

Edit: I'm not sure, but maybe there are missing links to some other translations as well, keep that in mind.