make parameterPostfix configurable using Event

[Shogoki]

Hey there,
What do you think about making the Config postfix configurable via the incoming Event?
I am using an in this way adjusted version of vault-maxi already for a couple of days.

Reason for this is, when running on Lambda i can simply use the same lambda function with multiple Triggers and parameters.

Any suggestions? If this works for you, I would be more than happy to create a PR for this.

[kuegi]

sorry for the late reply. sounds interessting. looking forward to the PR.