It should be possible to create collections outside collection root documents

Currently, there are two collection document types:

• "Collections", i.e. collection root
• "Collection", the actual collection document in which you display collected documents.
  A "Collection" can be created only in a "Collections".

What should be available:

• Users should be able to create a "Collection" outside a "Collections", from:
  • workspaces,
  • folders,
  • ordered folders.
• "Collections" should be available to users for creation.
• "Collections" should only be created by system in the user's personal workspace, when the user creates a "Collection" from the collect form.