MVP v5: Dynamic Collections

[paulpestov]

For showcasing Dynamic Collections it is necessary to implement a core behaviour of adding collections were not previously configured.

AC:

• In the top bar next to the list of active panels and their manifest titles there is a button to add new panel
• Upon click on that button the user will be presented with a popup that
  • Holds a text input for a new collection URL
  • A Tree Selection of known collections (known = preconfigured and entered via text input)
  • A click on a TextAPI item creates a new panel
• In the top bar, left to the list of active panels there is a button to open a global Tree Selection
• Upon click a Tree Selection panel appears left to the text panels that
  • Holds a tree of all known collections
  • Each collection is a root node
  • A click on a TextAPI item opens a popup with a selection for the further behaviour
    • A replacement of the content of any already opened panel
    • A creation of a new panel