Phosh private cleanup
This brings f/phosh-private back in line with the librem5 branch. The first patches simple cherry-pick stuff from the librem5 branch tht should have been done on f/phosh-private directly. The last patch fixes a crash when reconnecting phosh several times (caused by broken resource management).
Once this is applied we an safely merge f/phosh-private into librem5 and continue to develop the private interface there (which still should remain as minimal as possible).