Replace WayBack Machine PNG with SVG

[veyndan]

The benefit of using SVGs here over PNGs are that:

1. The SVGs are much more scalable than PNGs.
2. I think it's more "official"? I took this SVG from the one shown on the https://web.archive.org homepage, and just removed some unnecessary fluff.
3. The SVGs are significantly smaller at 13kB a piece, compared to the PNGs which are 74kB and 57kB. This is somewhat minor, since the PNGs weren't that big in the first place.
4. The last point is completely subjective, where I think the new SVG design looks slightly better, particularly on small devices (the lack of 3D effect makes it easier to read).

Before	After