Add form factors to desktop and appdata files

Closes #1

See merge request !2

Add gitlab-ci

See merge request Librem5/debs/ppm!1

ppm v0.0.4

This got broken when switching to the ModemManager1 API. Instead
of checking the error, check state upfront.

This allows us to keep needed interfaces around

This avoids stalling the UI. We mark async dbus calls
with a 'dbus_' prefix from now on.

We're using GtkApplication now

This allows us to get rid of our custom GtkBuilder loading

This allows us to get rid of our custom GtkBuilder loading

This will make referencing them simpler