Allow customizing user interface via configuration

[youngj]

It would be good to allow different deployments to customize the user interface without needing to fork the codebase. Customizable user interface elements could include:

• the stats displayed on the summary tab
• the default columns on the route table
• the tabs on the route screen
• the components within each tab on the route screen
• the content of the About page
• the content of the Home page