use more variables instead of hard-coding (fixes #3)

templates/caddy.service

@@ -0,0 +1,44 @@
+[Unit]
+Description=Caddy HTTP/2 web server
+Documentation=https://caddyserver.com/docs
+After=network-online.target
+Wants=network-online.target
+
+[Service]
+Restart=on-abnormal
+
+User=www-data
+Group=www-data
+Environment=CADDYPATH=/etc/ssl/caddy
+
+PIDFile=/run/caddy.pid
+ExecStart=/usr/local/bin/caddy -log stdout -agree -email={{ caddy_email }} -conf=/etc/caddy/Caddyfile -root=/var/tmp
+ExecReload=/bin/kill -USR1 $MAINPID
+
+KillMode=mixed
+KillSignal=SIGQUIT
+TimeoutStopSec=5s
+
+LimitNOFILE=8192
+LimitNPROC=64
+
+StartLimitInterval=600
+;StartLimitBurst=5
+RestartSec=60
+PermissionsStartOnly=true
+
+PrivateTmp=true
+;PrivateDevices=true
+;ProtectHome=true
+;ProtectSystem=full
+ReadWriteDirectories=/etc/ssl/caddy
+
+; The following additional security directives only work with systemd v229 or later.
+; They further restrict privileges that can be gained by caddy.
+; Note that you may have to add capabilities required by any plugins in use.
+;CapabilityBoundingSet=CAP_NET_BIND_SERVICE
+;AmbientCapabilities=CAP_NET_BIND_SERVICE
+;NoNewPrivileges=true
+
+[Install]
+WantedBy=multi-user.target