Research expeditions, cruises, etc

[pbuttigieg]

Add a short page to the book describing how to handle this group of entities.

There's often semantic confusion / confounding between research expeditions as Projects and as Events.

• When the metadata is about the "thing that happened" it should be typed as an Event.
  • Events can have other Events as parts, or be part of another Event
  • Events can also have Actions as parts, I'm not sure the converse is reasonable however.
  • One can sense this is the right type when there's more information about what happened rather than the admin around it.
• When the metadata is about the project within which the event occurred, then the Project or ResearchProject type should be used
  • One can sense this is needed when the Event type starts becoming overloaded with administrative information.

CC @pieterprovoost