Load Source Sans Pro for use in LoggedOutHomepage.tsx

Created by: rrhyne

The /search is .com homepage designs require the use of the Source sans font in a few areas on the logged-out homepage (Figma). As this font is only used on the homepage, it only needs to be loaded for the LoggedOutHomepage.tsx file.

Ideally, it would be used in styling in this manner:

--marketing-font: your magic here

font-family: var(--marketing-font);