Gpsd fixes Apr 2020

Hi this PR is starting the discussion on the changes required for the recent flurry of gpsd bugs/discussions on launchpad.

I have extensively tested the apparmor/pps changes already and had the security Teams +1 on it.

The packaging changes implement what was discussed/mentioned but are not yet tested - this part is meant as RFC to get things going. I'll later on run some tests as I get to it but I wanted to you see (and discuss) the intended changes already.

Links https://bugs.launchpad.net/ubuntu/+source/gpsd/+bug/1872175 https://bugs.launchpad.net/ubuntu/+source/gpsd/+bug/1872178 https://bugs.launchpad.net/ubuntu/+source/gpsd/+bug/1873415 https://bugs.launchpad.net/ubuntu/+source/gpsd/+bug/1872189