Add option to force the skyview to have the north up

[EmmanuelMess]

Is your feature request related to a problem? Please describe. The skyview rotates with the phone, this is confusing as in other software doesn't, like RTKLIB.

Describe the solution you'd like Add a button to force the skyview to have the north up. This also needs to be implemented for some of the map views I think.

Describe alternatives you've considered Rotating my phone, but there are calibration issues.

Additional context See #717.