[website] update to a colorful favicon

[chrisgervang]

Let's add some color back using our revived color logo. Our existing favicon was Uber branding.

Change List

• Switched all references from favicon.ico to favicon.png
• Also updated copyright in pydeck docs since it was out of date

[coveralls]

coverage: 91.217%. remained the same
when pulling 4dd0eb9 on chr/favicon
into 18e9c34 on master.

[felixpalmer]

Any chance to use a higher resolution image? For example on iPhone this will look blurry

[chrisgervang]

What's the size a favicon can be these days? I copied the size of the existing one

[felixpalmer]

I settled on an SVG for the A5 website: https://github.com/felixpalmer/a5/blob/main/website/docusaurus.config.js#L17 which is also built with docusaurus. Seems to work well in many contexts, mobile, favorites etc...

Here's how a5 & deck render as new tab shortcuts in Firefox: