Limited support for Folders by palette tools

[oconstant]

With Capella 5.0.0 and Requirements add-on 0.12.0:

• The "Requirements" palette tool does not allow showing Folders in diagrams.
• But the "All Linked Requirements" palette tool does allow showing Folders if they are already linked to Capella elements.

This looks a bit inconsistent. My suggestion would be to have the "Requirements" tool capable of showing Folders.

It is conceptually OK since every Folder is a Requirement anyway (Folder inherits from Requirement in the metamodel).
But more importantly, as a user I find it very convenient to be able to link Folders and Capella elements (just like Folders and Folders, or Folders and atomic/non-Folder Requirements). I assume the semantics to be the same as manually linking the Capella element to every atomic Requirement that is recursively contained in the Folder. So this mechanism saves a LOT of time in terms of modeling, model review, and change management (if I add a Requirement in a Folder that is linked to a Capella element, then semantically the Requirement is automatically linked to that element).