UDTF - wrap up work on supporting variable length inputs (w/Alex)

[dharhas]

PR https://github.com/omnisci/omniscidb-internal/pull/4025 (merged) implements a new Array UDF type.

• [x] Implement the new Array UDF support in RBC
• [ ] Demonstrate Array UDF usage in a Jupyter notebook

[pearu]

• [x] https://github.com/omnisci/omniscidb-internal/pull/4025 - Array support in Omnisci by Alex [MERGED]
• [x] https://github.com/omnisci/omniscidb-internal/pull/4133 - follow up to above by Pearu [WIP]
• [x] https://github.com/xnd-project/rbc/pull/19 - Array support for RBC [WIP]

[kcpevey]

Given some guidance, I can help with creating the demo notebook.

[kcpevey]

We've asked Venkat for an example use case from pandas that we can translate to a good example for this.