Add multiline text to array functionality  (Make large text blobs more readable)

Add ability to replace text strings containing newlines (aka `\n`) with an array of individual lines.

This could be added to `jmespath` as a simple `split()` function to complement the existing `join()` command.  But I think the most helpful bits would be in the `jsonformat` command.  This would make multiline text blobs much more readable, the purpose is less about programmatic manipulation.