Fix for docs: starting auto_rx.service after networking is ready

[janekska]

I faced a problem - after reboot service is started, but without web interface/service
( I guess that it is the same as in #598 (and could be connected with #585 and #586)).

Found the reason:

OSError: [Errno 99] Cannot assign requested address

Fixed by changing auto_rx.service file line:

After=syslog.target

to

Wants=network-online.target
After=network-online.target

So I guess - it would be good to update docs and sample auto_rx.service file.

[darksidelemm]

Possibly? However there are cases where people run auto_rx on standalone RPis without internet access.

What happens in that situation using the settings you mention? Is the presence of a loopback interface enough for it to work?