XcodeServerProxy (proxy, load balancer) #123
Description
In order to support buildasaurs/Buildasaur#180, we need to add a new object, XcodeServerProxy, which will look like a plain old Xcode Server on the outside, however on the inside it will talk to multiple real Xcode Servers, distribute work between them and when e.g. asked for Bots, will gather Bots from all real instances (and keep an internal map of which Bot lives on which instance).
This will get complicated, but is another step in powering awesome usecases which devs are coming up with - in this case, having a farm of Xcode Servers and distributing work between them.
All feedback is welcome, because I've never done anything like this. Should be fun.
(Note: this will require heavy tests to be written probably before we start implementing it to be able to lock down the behavior).