Secure systemd deployment

A bit more secure deployment of dumbproxy with SystemD, using maximum system isolation. Configuration files:

/etc/systemd/system/dumbproxy.service

[Unit]
Description=Dumb Proxy
Documentation=https://github.com/SenseUnit/dumbproxy/
After=network.target network-online.target
Requires=network-online.target

[Service]
EnvironmentFile=/etc/default/dumbproxy
DynamicUser=yes
StateDirectory=dumbproxy
Environment=HOME=%S/dumbproxy
ExecStart=/usr/local/bin/dumbproxy --bind-address='' $OPTIONS
TimeoutStopSec=5s
PrivateTmp=true
ProtectSystem=full

[Install]
WantedBy=default.target

/etc/systemd/system/dumbproxy.socket

[Socket]
ListenStream=443

[Install]
WantedBy=sockets.target

/etc/default/dumbproxy

OPTIONS=-auth basicfile://?path=/var/lib/dumbproxy/dumbproxy.htpasswd \
	-autocert

Enable service:

systemctl daemon-reload
systemctl enable dumbproxy.socket
systemctl start dumbproxy.socket