Initial parity cookbook

Supports installing multiple instances of Parity on the same machine,
running on different ports

Refs #15

site-cookbooks/kosmos-parity/templates/default/parity.systemd.service.erb

@@ -0,0 +1,11 @@
+[Unit]
+Description=Parity Daemon (<%= @environment %>)
+After=network.target
+
+[Service]
+ExecStart=/usr/bin/parity --config <%= @config_file %> $ARGS
+User=parity
+Group=parity
+
+[Install]
+WantedBy=default.target