Add example systemd unit

[glensc]

Could be just stored as file as example in the repository.

[glensc]

here's kickstart file

# /etc/systemd/system/ssh3-server.service
[Unit]
Description=SSH3: faster and rich secure shell using HTTP/3
After=network.target

[Service]
ExecStartPre=mkdir -p /etc/ssh3
ExecStartPre=sh -c 'test -e /etc/ssh3/cert.pem || openssl req -x509 -sha256 -nodes -newkey rsa:4096 -keyout /etc/ssh3/priv.key -days 3660 -out /etc/ssh3/cert.pem -subj "/C=XX/O=Default Company/OU=XX/CN=selfsigned.ssh3" -addext "subjectAltName = DNS:selfsigned.ssh3,DNS:*"'
ExecStart=/usr/local/sbin/ssh3-server -cert /etc/ssh3/cert.pem  -key /etc/ssh3/priv.key

[Install]
WantedBy=multi-user.target

to use:

systemctl daemon-reload 
systemctl start ssh3-server