Install config files to /etc/default/

Related: OS#4326
Change-Id: Ibff534c2f247557bb4eb0f72b8babe85ad0b315b
diff --git a/debian/osmo-remsim-bankd.install b/debian/osmo-remsim-bankd.install
index 58de089..4e1d6a5 100644
--- a/debian/osmo-remsim-bankd.install
+++ b/debian/osmo-remsim-bankd.install
@@ -1,2 +1,3 @@
 usr/bin/osmo-remsim-bankd
 lib/systemd/system/osmo-remsim-bankd.service
+etc/default/osmo-remsim-bankd