We want to be able to send web notifications but currently send.js is typed using DeviceType which doesn't include web. This diff changes it to use the Platform type and changes some names to fit better. There should be no behaviour changes introduced in this diff.
Create a new account on iOS and check if notifications still work.
One place where the names aren't changed are the Delivery objects which contain a deviceType field that after this diff will contain values from Platform. But it's saved inside the database as json and we would have to support both deviceType field (for older notifications) and platform fields (for newer notifications) when rescinding notifications so I'm not sure if it's worth it.