feat(selfhost): add persistent host update service

scripts/fedeo-updater.service

@@ -0,0 +1,33 @@
+[Unit]
+Description=FEDEO host update service
+Wants=network-online.target
+After=network-online.target docker.service
+Requires=docker.service
+
+[Service]
+Type=simple
+User=root
+Group=fedeo-updater
+Environment=HOME=/root
+Environment=PYTHONDONTWRITEBYTECODE=1
+EnvironmentFile=-/etc/fedeo/updater.env
+ExecStart=/usr/bin/python3 -B /usr/local/lib/fedeo-updater/selfhost-update-service.py serve --directory @FEDEO_DIRECTORY@
+Restart=on-failure
+RestartSec=5s
+KillMode=mixed
+TimeoutStopSec=infinity
+UMask=0077
+RuntimeDirectory=fedeo-updater
+RuntimeDirectoryMode=0750
+RuntimeDirectoryPreserve=yes
+NoNewPrivileges=true
+ProtectSystem=full
+ProtectKernelTunables=true
+ProtectKernelModules=true
+ProtectControlGroups=true
+RestrictSUIDSGID=true
+StandardOutput=journal
+StandardError=journal
+
+[Install]
+WantedBy=multi-user.target