Remove unnecessary explicit conformance to Equatable

[sergeysmagleev]

I noticed that the models in Order.swift explicitly implement the == function to conform to Equatable. This means that each time a model is updated, this method must be updated too, which makes it easy to make a mistake by forgetting to do so. This could be avoided by making all properties inside the models conform to Equatable too.
Also, lhs.date.timeIntervalSince(rhs.date) < 1.0 comparison wasn't working correctly because for each case when rhs is later than lhs it would always return true.
This also revealed an error in the Unit Tests when OrdersWorker.updateOrder method wasn't returning the correct order with the updated date in it.
Therefore I have:

• Removed all instances of explicitly implemented == method
• Declared necessary Model structs as conforming to Equatable
• Made updateOrder method inside OrdersWorkerTests test suite return the Order object passed to it inside the completionHandler instead of the static mock object from OrdersWorkerTests.testOrders

[Pratik-Somaiya]

👍