[viz]: refactored navbar, build out help page
[viz]: refactored navbar, build out help page

openconnectome/open-connectome,neurodata/ndstore,openconnectome/open-connectome,openconnectome/open-connectome,neurodata/ndstore,openconnectome/open-connectome,openconnectome/open-connectome,openconnectome/open-connectome,neurodata/ndstore,neurodata/ndstore