Allow users to define language transformations

**Is your feature request related to a problem? Please describe.**
I want to write my code in CoffeeScript. Others will probably want to use TypeScript.

**Describe the solution you'd like**
I would like to specify in one place, how to convert my code to JavaScript or Python, which are currently supported. It's OK if I need to use JavaScript or Python to specify the conversion. Thereafter, I should be allowed to enter code where code is currently allowed in whatever language I want, as long as I've done the above first.

**Do you have a workaround?**
Currently, I would have to compile the CoffeeScript to JavaScript before entering the code into Pipedream. That really goes against the ease of use that Pipedream provides.

**Comparable features in other tools?**
Not that I know of