Add icon for NymVPN - #3949

Concept looks good to me. Visual contrast might improve with a lighter background or a darker foreground element: some icons go down to #3F3F3F for foreground elements (only). That said, the example under "New:" above passes WCAG AAA for large text at https://webaim.org/resources/contrastchecker/, as well as AA for graphical objects. Maybe my eyes are just glitching seeing it next to the higher contrast OG one!

There is a matrix transform in the 16px icon that need applying to the coordinates inside its group, and some misalignments around the shadows and highlights of the N. I'll have a go at fixing those later today, and hopefully I'll be able to update your branch for a quick check-in beoire merging.

@achadwick I didn't know about the contrast checker site, thank you! I'll start using it now
I can check for the matrix transform and misalignments now and you can double check me after that

@achadwick I fixed the matrix transform (feel free to double-check). I also added a tiny bit more warmth (upped the red) to the green background color.

I didn't find any misalignment, but I might have missed something.

@wilwarindi It didn't need much, just alignment things. A couple of the highlights had just been copied and pasted at a different size without remaking it.

The foreground:background contrast ratio meets accessibility standards, but it could be improved to be just over 7.0 without being too far away. I actually used Gpick's LCH colour adjuster to avoid messing with the hue and saturation too much; not sure what WebAIM use!

#454545/#45CF7B (4.77:1) (unchanged)

#323232/#45CF7B (6.38:1) (fg- (darker))

#323232/#55DD87 (7.37:1) (fg-, bg+)

Perhaps I'm just oversensitive to black-on-midtone contrasts, but I think the last one is a real improvement without distorting the colours and design too much. The first one is quite a bare pass for AAA large text, and it feels it. The last one is AAA-rated for small text - small icon sizes - too. What do you think?

And aesthetically: does the background green look OK for the above, and not too acidic/bright on a dark background? I don't use a dark theme, so it'd be good if someone could check that.

I don't think it looks too bright, personally, but I don't know if the decision of the color is up to me.
Re: alignment, I thought I'd made each one from scratch for every icon size, but I might have missed something. I'm gonna go double check my other PRs.
Thank you for all you feedback and explanations, BTW!

@achadwick @wilwarindi I think it looks nice on dark theme as well, the contrast improvements are nice

Thanks for the feedback. I'll go with #323232 on #55DD87 for now, and merge.