Support for multidimensional arrays

[jmlord]

Arrays in the Run UI and the pipeline editor are entered as a comma-separated list. This does not allow for multidimensional arrays.

Current workaround in pipeline editor: In order to produce and array of arrays, one can connect many arrays to the same input.
There is no workaround in run ui.

For all [][] values, we could ask the user to explicitly put brackets as such: [[a1, a2], [b1, b2]]