Add the concept of 'investigation'

[ElDeveloper]

Often times studies are created and generate data independently, however in order for any of these to be generally useful, they need to be combined as a single investigation. An investigation is essentially a study container.

[antgonza]

This is already in the DB, we only need to expose it. The idea is to group different studies under a single investigation. Only owners (and their guests) can group the studies under an investigation.