Split permissionnode into two config options
You can now give permission to send and accept trades separately! An example use case of this is if you only want VIPs to be able to send trade requests but want them to be able to trade with anyone.
Changes:
- permissionrequired ---> permissions.required (default: false)
- permissionnode ---> permissions.send (default: tradeplus.send)
- [new feature] permissions.accept (default: tradeplus.accept)