Add new nav bar to Gastby site

[Gkrumbach07]

As a visiter of Thoth website, I don't want to be overwhelmed by an extensive nav bar, however I still want to be able to navigate to most of Thoths pages through links.

Acceptance Criteria

• Reduce the number of links on top to only Projects, Community, Resources, Documentation
• Each link can dropdown into a list of other links. i.e. Resources can hold most of the links that were on the current nav bar
• add Thoth logo that links back to homepage on left side of the nav bar
• Call to action should link to our getting started docs

Additional Info
Nav Bar mockup

Drop down can display links in a multi column modal