osmo-remsim-server: add systemd service script

Change-Id: I310a78b49a8a17e4f954179553ed2a3376e3bd50
diff --git a/contrib/systemd/osmo-remsim-server.service b/contrib/systemd/osmo-remsim-server.service
new file mode 100644
index 0000000..e91e08b
--- /dev/null
+++ b/contrib/systemd/osmo-remsim-server.service
@@ -0,0 +1,12 @@
+[Unit]
+Description=Osmocom Remote SIM Server
+
+[Service]
+Type=simple
+Restart=always
+ExecStart=/usr/bin/osmo-remsim-server
+RestartSec=2
+
+[Install]
+WantedBy=multi-user.target
+