add merchant script

scripts/merchant.conf.template

@@ -0,0 +1,19 @@
+[main]
+host = hostname of the machine where you run this program
+port = choose a port number
+password = choose a password
+
+[db]
+instance = the hostname of your sql server
+name = the database name
+user = your database username
+password = your database password
+
+[electrum]
+server = the electrum server you will use
+mpk = the master public key of your wallet (in hexadecimal)
+
+[callback]
+received = URL where we POST json data when payment has been received
+expired = URL where we POST json data if payment has expired
+password = password sent in the json data, for authentication