Add github link for congress site development

[vash3g]

Is your feature request related to a problem?

Please add the github logo near the AGA logo to enhance interest in contributing to the congress site in the future.

Describe the feature you'd like to see on the Go Congress Website.

Please add the github logo near the AGA logo to enhance interest in contributing to the congress site in the future.

[neagle]

Technically the AGA logo is part of a feature on the site to display Congress sponsors, though that hasn't been a much-used feature of recent Congresses. I think adding a link to the Congress github as a way of encouraging involvement is a nice idea, but I think it's worth keeping it separate from the sponsors area.

[michaelhiiva]

Maybe, then a GitHub link could be placed in the primary navigation bar or the GoCongress Website could provide information on it being OpenSource in the FAQ page (https://www.gocongress.org/2021/content_categories/77).