run as source

[albfan]

work from @derekdai rebased here. still not working but lot of interesting improvements

Tested using https://gitlab.gnome.org/GNOME/gnome-network-displays as source and this branch as sink.

Whatever is still missing here (probably use a portal to share the screen) should be found collecting dbus communication, journalctl and miraclecast logs

fixes #4

[albfan]

We need to stop timeout on go neg to connect, and open manual miracle-dhcp server and client to reach the connected signal. Something is broken there.

In fact, only miraclecast working as a client (no group owner) works, that's why sometimes external sources do not work.

[tiziodcaio]

Maybe try to keep the "compatibility" with other init systems... I know everyone love systemd, but I think that we should be able to chose freely