device-pine64-pinebookpro: move to community

This seems to meet the requirements for community (even though some things are still WIP, like improving stability)

@minlexx @MartijnBraam please push commits to add yourselves as maintainers of the device package if you want. You've both done far more work on this device than I have. I added myself since I plan to use mine, and someone had to be there to meet the requirement :P

Reminder of "moving to community" criteria:

https://wiki.postmarketos.org/wiki/Device_categorization#Moving_between_categories