Allow expressions in exception types

[jordan.harvey.norfolkcc]

Currently you can use an expression the exception detail, however in some cases it would be useful to raise dynamic exception types based on the response of an API request.

What I'd like to build is a rules engine that can "tell" a process to perform various core actions, one of those is around raising an exception which might look something like this:

"actionType": "RAISE_EXCEPTION",
"actionPayload": {"type": "Business", "reason": "Business reason here"}

Currently I would have to create a choice stage and map each exception type which is very inefficient, especially if implementing across different processes.. This will also lead to a lot of code duplication and long term quality / maintenance issues.