Update logo to 2021 edition

[garrett]

Not 100% done yet — and I may need to optimize the logo a little more too. But here's a preview of what I currently have.

Live preview: https://garrett.github.io/cockpit-project.github.io/

Before:

After:

It's quite subtle.

• Changed text to RedHatDisplay. (It's quite similar, but a little different. As it's the font family we use and it's quite close, we might as well just use it directly.)
• Tweaked kerning optically.
• Embiggened the plane.
• Thinned down the outline to be the same weight as the text.

[garrett]

This is one of those things where an organization spends 100 million bucks with a design firm and it results in a logo that only designers will notice the difference. (Minus the design firm and 100 million bucks.)