Improve contribution guideines and readme

[goodideagiver]

What issue I want to solve

I want more people to contribute to bewebdev.com

Proposed solution

Improve readme with better structure of the text and improve guidelines of contributing to our repo.

What steps could be done to achieve that:

1. Write step by step tutorial how to clone repo, create branch, write commit messages etc.
2. Improve instalation instructions (project setup) docs
3. Describe labels in our issues page (idk if that's needed, labels could serve only me and @Willaiem to organize issues)

Related issues

199