Rewrite README.md

[toby63]

It should maybe contain more useful information:

1. Introduction:
   • Link to handbook page (The handbook website can be found here:)
   • If you want to contribute follow the instructions below
2. Describe how to contribute:
   • git clone
   • install necessary software
   • how to edit it (language used is markdown etc.)
   • test your changes by building the website & check for the changes in your own browser
   • create a pull request
3. Link to contribution guidelines:
   • language and style
   • allowed tags
   • signed commits(?)
   • etc.

[ThaHobbyist]

Hello, @toby63 I'm new here and want to take this up as my first issue. Any kind of assistance is welcome