Add syslog hook in skywire apps and fix syslog in some visor modules

[ersonp]

Describe the bug
The logs of the skywire apps are not saved to syslog so we need to add a hook.
Some of the visor module logs namely dmsgC, stcpr, dmsg_pty, stcp and maybe others are not being saved in syslog

Environment information:

• OS: e.g. Linux
• Platform: Linux 5.11.0-38-generic x86_64

Steps to Reproduce
Steps to reproduce the behavior:

1. Install and start syslog-ng sudo syslog-ng -f ./syslog-ng.conf -edv with this config

# Default syslog-ng.conf file which collects all local logs into a
# single file called /var/log/skywire tailored to container usage.


@version: 3.29
@include "scl.conf"

source s_local {
	internal();
};

source s_network {
	default-network-drivers(
		# NOTE: TLS support
		#
		# the default-network-drivers() source driver opens the TLS
		# enabled ports as well, however without an actual key/cert
		# pair they will not operate and syslog-ng would display a
		# warning at startup.
		#
		#tls(key-file("/path/to/ssl-private-key") cert-file("/path/to/ssl-cert"))
	);
};

destination d_local {
	file("/var/log/skywire");
	file("/var/log/skywire-kv.log" template("$ISODATE $HOST $(format-welf --scope all-nv-pairs)\n") frac-digits(3));
};

log {
	source(s_local);
	source(s_network);
	destination(d_local);
};

2. Run ./skywire-visor skywire-config.json --syslog localhost:514
3. Check terminal
4. Check syslogs at sudo cat /var/log/skywire