add systemd unit for rootless podman container

ppf.container.service

@@ -0,0 +1,36 @@
+[Unit]
+Description=PPF Proxy Validator Container
+After=network-online.target
+Wants=network-online.target
+
+[Service]
+Type=simple
+Restart=on-failure
+RestartSec=30
+TimeoutStartSec=90
+TimeoutStopSec=30
+
+# Container runtime
+ExecStartPre=-/usr/bin/podman stop -t 10 ppf
+ExecStartPre=-/usr/bin/podman rm -f ppf
+ExecStart=/usr/bin/podman run \
+    --name ppf \
+    --rm \
+    --log-driver=journald \
+    --network=slirp4netns:allow_host_loopback=true \
+    -v %h/ppf/config.ini:/app/config.ini:ro,Z \
+    -v %h/ppf/servers.txt:/app/servers.txt:ro,Z \
+    -v %h/ppf/data:/app/data:Z \
+    -e PYTHONUNBUFFERED=1 \
+    localhost/ppf:latest \
+    python proxywatchd.py
+
+ExecStop=/usr/bin/podman stop -t 10 ppf
+
+# Logging
+StandardOutput=journal
+StandardError=journal
+SyslogIdentifier=ppf
+
+[Install]
+WantedBy=default.target