Re-evaluate the goal of the Readme

[BasThomas]

At the moment, the Readme is one big blob of information of about 3 pages. I feel like we should re-evaluate what we want to achieve with the Readme and split off some superfluous "Readme"-information to a docs folder or the like.

[JoeSSS]

I also have a feeling that Readme is a bit polluted. But in the same time I don't see any piece of information that I don't want to see on the first page, except maybe Xcode configuration and physical devices config. For these two we can simply add a link