Finalize the DimensionSwitcher Component/Functionality

[Inkdpixels]

Currently we embedded a data-fixture for the DimensionSwitcher in the ContextBar Container. Real data needs to be rendered and the functionality for the switch needs to be implemented.

[GerDner]

PR #74

• initialState
• https://github.com/JedWatson/react-select as select component
• initial work for wrapping react-select (option component)

[hlubek]

This is implemented with #323, I'll add a separate issue for the creation of a new node variant through the switcher (through the modal asking for a new translation / copy of existing content)