added setup info for PiCade

[rdmueller]

just a proposal. Feel free to edit it.

[Vegz78]

Hi @rdmueller,

Thanks for the PR! Even though I appreciate the proposal and the chance to learn how to follow through a PR from this side of the repo ownership, I feel the proposed text, specific only for the Picade is out of place inside the main readme.md document.

Ideally, since broad controller support is crucial for the usefulness of McAirpos, I maybe should've had a wiki dedicated to the various tested controllers, and moved some information from the main readme.md.

However, since more documents also means more follow-up work, I have chosen to use the issues section as a wiki/knowledge base instead, with mention of the relevant solutions for the various popular and tested controllers high up in the readm.md, like this:

If you could be so kind to as add your PR tekst as a concluding summary for the Picade at the end of your issue instead, I will add a similar line for the Picade in the readme.md, with attribution for your help and link to this issue/summary.