Add white outlines to the logos to look nicer on dark mode

[jaybosamiya-ms]

This PR updates the Verus logos to have white borders to perform this change (screenshots taken in dark mode):

---

Details

I wrote the following filter to wrap around the outermost group of the SVGs for the logos; it essentially merely adds a 2.5 width white-colored dilation around any object where the filter is applied. The width/height of the images needed to be updated to account for this (from 106 -> 106+2x2.5 == 111), but otherwise, no other changes were necessary.

    <filter id="groupborder" filterUnits="userSpaceOnUse" x="0" y="0" width="111" height="111">
      <feOffset in="SourceGraphic" result="input" dx="2.5" dy="2.5" />
      <feOffset in="SourceAlpha" result="inputAlpha" dx="2.5" dy="2.5" />
      <feMorphology operator="dilate" in="inputAlpha" radius="2.5" result="dilated" />
      <feColorMatrix type="matrix" in="dilated"
                     values="-1 0  0  0  1
                             0 -1  0  0  1
                             0  0 -1  0  1
                             0  0  0  1  0" result="whitened"/>
      <feComposite in="input" in2="whitened"
                   operator="over" result="output"/>
    </filter>

Also, I've regenerated the PNGs (via inkscape -w 333 -h 333 verus-color.svg -o verus-color.png, ...; followed by optipng -o7 to squeeze PNG sizes down).

[utaal]

Thank you for looking into this. Let me look into alternatives to accomplishing readability in dark mode. I find the white outline quite jarring as proposed in this PR.

[tjhance]

would it look better if the borders were thinner?

[utaal]

I pushed a commit that made the title legible in dark mode (that was certainly a necessary improvement, thank you for noticing the issue). I don't think we should add outlines to the primary svgs that we distribute from the "logos" page (they'd for example interfere if someone used them on slides with a light but not white background).

I personally don't mind much that the logo is a bit muted in dark mode, but we could consider variations of the logo colors itself that would work better on a dark background.

@jaybosamiya-ms is the fix on main sufficient for now?
Thank you for noticing the issue, and prompting the change.

[jaybosamiya]

The updates to main look reasonable for now; I think the logo still needs updates for dark mode somehow, but at least with the text not being fully dark, it is less of an issue.

Agreed on the white outline looking a bit jarring, especially on smaller screens (I had originally done it on a larger screen, where it looks more reasonable).

Anyways, next one to be fixed is the GH org logo that blends away into the darkness. It can prob be fixed by just having the org logo having a white background instead?

[utaal]

Regarding the GitHub org logo, a white background should work, I'll give it a shot! Can I close this for now?

[jaybosamiya-ms]

Sure, feel free to close; the main issue is fixed at this point. I'm not closing it right now, as a reminder of the GH org logo test, but once you're done with that, feel free to close this.