Add batchMap to batch scripts to share data across multiple executions of the script for a single batch

[rbeckman-nextgen]

Right now users are forced to use the global or global channel maps to share data across multiple invocations of a batch script. Instead there should be a map available that is shared across each script execution for a single batch. Once all messages in the batch have been processed, the batchMap is thrown away.

Imported Issue. Original Details:
Jira Issue Key: MIRTH-4439
Reporter: narupley
Created: 2019-07-15T07:30:36.000-0700

[atupaitso]

Hi, we are very interested in this function, because when trying to process a JSON in blocks of 100 elements, we are mixing the executions of other messages that come in at the same time.
Would it also allow to put the batch channel in multithreaded mode?