* Cross compile wheel for armv7l (Raspberry Pi 4) using Github Actions CI
Fixes#6567
* Added instruction on how to install Kivy on a Raspberry Pi 4
* Do not package the examples in the wheel
* We can not upload armv7l wheels to PyPI
* Remove all references to KivyPie
* Merge the installations instructions for Raspberry Pi's together
* Build the armv7l wheel on Stretch as well
* Create a copy of the wheel with a armv6l suffix
* The wheels are Raspberry Pi specific
Kristian Sloth Lauszus