Replace logo with SVG that includes name in proper typography

[ryanahamilton]

related: #10953

Replaces the PNG + HTML text version of the Airflow logo with an SVG that yields both the pinwheel and "Airflow" text. The prior implementation simply used the default font-family (Helvetica Neue) for the brand name, where this implementation uses the brand font-family (Rubik). This ensures that brand font is always locked up with the logo in cases where an end-user may apply a custom theme (e.g. different default font-family).

I left the old static asset (pin_100.png) in the file system as it appears to still be in use by a Slack Operator.

If you stare long enough, you'll see the typography differences 😃

Before	After

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[ashb]

I don't see where the font is used?

How big is the SVG? Is it worth making it an external resource so it's cached/only requested once?

[ryanahamilton]

@ashb "I don't see where the don't is used?" typo?

For smaller icon/logo SVGs, I typically opt for inline rendering and forgo the extra request.