Update "Getting Started" tutorial and README

[jwitz]

Description

What is the current behavior?

What is the new behavior?

This PR updates the style and wording of our "Getting Started" documentation without disrupting the core content. I tried to make it easier to follow the quickstarts and to understand the benefits of the SDK

Does this introduce a breaking change?

Checklist

• [ ] Created tests which fail without the change (if possible)
• [X] Extended the README / documentation, if necessary