Add header to Discourse that allows us to do things like link to website and campaigns

UPDATE: I used custom header links and custom header links (icons) to add simple links. I tried the more complex Header submenus and Brand header theme component, but they caused problems and I ultimately decided that they added unnecessary complexity. Moved to done for now but keeping the topic open in case this conversation needs to be revisited in a future website redesign.

See a potential header design here:

Options of Adding a Header

Custom CSS