Add an option to change DNA bases to cylinders - Ribbon/Cartoon style

[julioarvellos]

Hello, Brady!
I'm working with some DNA structures from PDB, and I just now realized that the bases are represented as planes (distorted cylinders with 4 vertices). It is interesting to have the option to change the bases from planes to cylinders, as it looks more integrated with the round backbone.

Comparison

And where the parameres are

[BradyAJohnston]

I previously avoided exposing these options to reduce the number of inputs for the nodes, but this was also pre-panels I think. I think having a panel for nucleic acid-specific options is reasonable, and would just require the exposing of the internal options that already exist that you have pointed out so I'm happy to do that :)