Add copyright banners
Add Liberator API

Remove components like menu and menuitem, these are not used.

Use modular's using dependency form to remove explicit dependency
declaration system formation.
Add useful refers to user ns
Incorporate example drugs data

Path to the drugs data JSON files served by Liberator must be configured in
`$HOME/.stentor.edn` under the `:drugs-data` key.
CSS tweaks

Drop down now has rounded corners and box shadows