Consider using ngl instead of pv

[heralden]

I don't remember if we chose pv over ngl for some specific reason, or we didn't know about ngl.

https://github.com/arose/ngl

NGL seems to be actively developed as opposed to abandoned (which pv is) and is used by RCSB. It uses the standard coloring scheme for secondary structure, and also shows a tooltip when hovering over the strands. I subjectively think the models look prettier as well. [=

If it's not too much work, we might swap out pv for ngl.

Here's a comparison between pv and ngl, respectively, using secondary structure coloring of 5VPZ.

[anu-shree]

I want to work on this issue. Please assign this to me.

[heralden]

@anu-shree Please go ahead!