Summary:
Moved all logic per device type we support to its own dir, including tools and utilities around it, which makes it easier to consolidate logic and decouple in turn per device type.
Per type, all logic can be found in
`server/devices/(desktop|metro|android|ios|webapp)`
Reviewed By: timur-valiev
Differential Revision: D30277817
fbshipit-source-id: 2b5339c363d5d31ceeba07cec03826fc67cf3748
