remove yarml import in tools.js

Author: NickOvt

lib/tools.js

@@ -16,7 +16,6 @@ const ipaddr = require('ipaddr.js');
 const ObjectId = require('mongodb').ObjectId;
 const log = require('npmlog');
 const addressparser = require('nodemailer/lib/addressparser');
-const yaml = require('js-yaml');
 
 let templates = false;