Add a check box that allows JSONata transformations to be performed without splitting

[jhorbulyk]

Currently, by default any JSONata expression that evaulates to an array is automatically split. For backwards compatibility we need to preserve this functionality. However, we should add an option not to perform this splitting as a checkbox.

[hannah-bulmer]

This issue was opened in a PR by me and later closed because emitting an array of data causes our passthrough to break as it is currently designed. It was decided it is not a good idea to put this functionality in right now until the passthrough is fixed/changed, so the issue is currently blocked

Closed PR is here: #13