WIP: Native GPIO

- dummy and Linux sysfs GPIO drivers for native
- minor PIR driver test fix

TODO:
- [ ] add signal mode for sysfs driver
- [ ] test sysfs driver on raspberry PI
- [ ] add control method for dummy interface
I was thinking of making this configurable from the outside because the host might not have all as many GPIOs.. I wasn't sure how to solve the `_EN` setting and just ignored it - adding to TODO