Server pool entity
Adds MachineEntity class for use in server pools
Server pool tests use EmptySoftwareProcesses as the pool member spec
Update MachineEntity with attributes class from Docker
Addresses server pool review comments
Server pool machine license header and indentation
Log yaml on REST createApp call
Reduce logging on LocationUsageManager.recordLocationEvent
This closes #11
Use findUniqueSshMachineLocation helper in SshFeed
Set summary for MachineEntity ssh task