configure.ac + debian: Add systemd service file support

Closes: OS#4326
Change-Id: I0d7b6562c1127f005ddbd47298c03942ac3d241d
diff --git a/debian/osmo-remsim-client.install b/debian/osmo-remsim-client.install
index 8e73dc1..85ffb82 100644
--- a/debian/osmo-remsim-client.install
+++ b/debian/osmo-remsim-client.install
@@ -1 +1,2 @@
 usr/bin/osmo-remsim-client*
+lib/systemd/system/osmo-remsim-client*