Add abstract dropdown page

[MaHaWo]

• adds a simple dropdown page with the actual content being passed as arguments.
  • add component for selection of categorical data
  • add component that eats an array of data objects
• creates a dummydropdown component to see how it works.
• adds routes from frontpage to dropdown to next dropdown page, just to make it do something for now.
• adds route for infopage (temporary).

[MaHaWo]

• changes since last discussion:
  • get rid of js class
  • componentize the data selection a bit better
  • make the selection element more exchangeable

[MaHaWo]

@lkeegan you want to have another look?

[lkeegan]

lgtm!