Add Debian packaging via cargo-deb (closes: #4)

* Add the required metadata to `Cargo.toml`
* Add a systemd service unit file
* Use `Rocket.toml.example` as the default configuration

Cargo.toml

@@ -21,3 +21,29 @@ rocket = { version = "0.5.0-rc.2", features = ["json"] }
 serde = "1.0.116"
 toml = "0.5.6"
 url = "2.2.2"
+
+[package.metadata.deb]
+maintainer = "Paul van Tilburg <paul@luon.net>"
+copyright = "2022, Paul van Tilburg"
+depends = "$auto, systemd"
+extended-description = """\
+Solar Grabber is web service that provides a REST API layer over various cloud
+sites/services/APIs to get statistical data of your solar panels.
+
+It currently supports the following services:
+
+* Hoymiles: https://global.hoymiles.com
+* My Autarco: https://my.autarco.com
+"""
+section = "net"
+priority = "optional"
+assets = [
+  ["README.md", "usr/share/doc/solar-grabber/", "664"],
+  ["Rocket.toml.example", "/etc/solar-grabber.toml", "600"],
+  ["target/release/solar-grabber", "usr/sbin/solar-grabber", "755"]
+]
+conf-files = [
+  "/etc/solar-grabber.toml"
+]
+maintainer-scripts = "debian/"
+systemd-units = { unit-name = "solar-grabber" }

debian/solar-grabber.service

@@ -0,0 +1,47 @@
+[Unit]
+Description=Solar Grabber API web server
+After=network.target
+
+[Service]
+Type=simple
+
+AmbientCapabilities=
+CapabilityBoundingSet=
+DynamicUser=yes
+LoadCredential=solar-grabber.toml:/etc/solar-grabber.toml
+LockPersonality=yes
+MemoryDenyWriteExecute=yes
+NoNewPrivileges=yes
+ProtectClock=yes
+ProtectControlGroups=yes
+ProtectHome=yes
+ProtectHostname=yes
+ProtectKernelLogs=yes
+ProtectKernelModules=yes
+ProtectKernelTunables=yes
+ProtectProc=noaccess
+ProtectSystem=strict
+PrivateDevices=yes
+PrivateMounts=yes
+PrivateTmp=yes
+PrivateUsers=yes
+RemoveIPC=yes
+RestrictAddressFamilies=AF_INET AF_INET6
+RestrictNamespaces=yes
+RestrictRealtime=yes
+RestrictSUIDSGID=yes
+SystemCallArchitectures=native
+SystemCallFilter=@system-service
+SystemCallErrorNumber=EPERM
+UMask=0077
+
+ExecStart=/usr/sbin/solar-grabber
+Restart=on-failure
+RestartSec=10
+StartLimitInterval=1m
+StartLimitBurst=5
+
+Environment="ROCKET_CONFIG=%d/solar-grabber.toml"
+
+[Install]
+WantedBy=multi-user.target