[#223] Debian packaging

Debian package includes:
 - user creation;
 - directories and permissions;
 - unit file for systemd

Signed-off-by: Dmitriy Zabolotskiy <d.zabolotskiy@yadro.com>

debian/neofs-http-gw.preinst

@@ -0,0 +1,35 @@
+#!/bin/sh
+# preinst script for neofs-http-gw
+#
+# see: dh_installdeb(1)
+
+set -e
+
+# summary of how this script can be called:
+#        * <new-preinst> `install'
+#        * <new-preinst> `install' <old-version>
+#        * <new-preinst> `upgrade' <old-version>
+#        * <old-preinst> `abort-upgrade' <new-version>
+# for details, see https://www.debian.org/doc/debian-policy/ or
+# the debian-policy package
+
+
+case "$1" in
+    install|upgrade)
+    ;;
+
+    abort-upgrade)
+    ;;
+
+    *)
+        echo "preinst called with unknown argument \`$1'" >&2
+        exit 1
+    ;;
+esac
+
+# dh_installdeb will replace this with shell code automatically
+# generated by other debhelper scripts.
+
+#DEBHELPER#
+
+exit 0