[WIP] Fairphone 2 support

It's not tested yet because I can't flash the system.img via fastboot.

[20:23:30] (native) flash system image
target reported max download size of 536870912 bytes
Invalid sparse file format at header magi
erasing 'system'...
OKAY [  0.293s]
sending sparse 'system' 1/2 (524285 KB)...
OKAY [ 16.480s]
writing 'system' 1/2...
FAILED (remote: Unknown chunk type)
finished. total time: 16.782s

It's maybe a problem with the lk/fastboot implementation on the FP2 but I can't say for sure.

I feel like we did look at that, but it wasn't necessary, as we only ran into it when flashing userdata with a lot of things in it

(quote from a fairphone dev)

But everything in these two packages compiles fine.