Tidying of OutputStreamCfg syntax

John Derek Chapmanrequested to merge
jchapman/athena:OutputStreamCfg_23.0 into 23.0

A number of clients of OutputStreamCfg go on to manually set AthenaOutputStream.TakeItemsFromInput immediately afterwards, so to save a few lines of code this merge request adds an extra optional argument to OutputStreamCfg to take care of this.

Merge request reports