Add ability for distributor to optionally overwrite site/app id of all outgoing PDUs

[timpokorny]

Summary

After integrating a large number of sites, a common problem was site/app ID clashes. For all DIS connections, the distributor can be assigned its own DIS site/app ID. An option should be added to override any incoming PDUs with the values configured in the link and thus move control to a more manageable location.

Acceptance Criteria

Once complete:

• There shall be another setting in the distributor configuration that allows it to overwrite all incoming PDUs with its own site/app ID