Remove EMBB event log model
This is a really old data model which I think was at one time a competing model for EM observations? There are literally only 31 of these in the production database, created only between November 11, 2014, and April 20, 2015, and half of them are associated with Test events.
This might also allow us to remove a bunch of noise from the API root, like wavebands and so on.