Update DP_HEADER to include filename in message

[JakeHuneau-LSPedia]

No description provided.

[uhurusurfa]

I understand why you want to add this but it cannot be added because:

1. The AS2 specification does not require the sender to transmit the file name
2. It is a breaking change for existing deployments.

The solution is to make all the messages configurable through configuration properties that can be passed in at startup.

Note that the existing messages match the defined AS2 default messages.

The suggested way to support customising the messages for your deployment is to encapsulate all the message strings into a static map with a string identifier as the key and then allow the system to override the strings at startup through added logic in the session configurator.

[JakeHuneau]

Understood and fair, feel free to reject and close this