Implemented automatic diff

[thinkharderdev]

We should be able to use a Schema[A] to automatically diff values of type A.

To do this we should add a method like so

trait Schema[A] { self =>
  def diff(thisValue: A, thatValue: A): Diff =  DiffAlgorithm.fromSchema(self)(thisValue,thatValue)
}

Where we have DiffAlgorithm and Diff that look something like

trait DiffAlgorithm[A] { self =>
  def apply(thisValue: A, thatValue: A): Diff
}

object DiffAlgorithm {
  def fromSchema[A](schema: Schema[A]): DiffAlgorithm[A] = ???
}

sealed trait Diff
object Diff {
  final case object Identical extends Diff
  final case class Number[A : Numeric](distance: A) extends Diff
  final case class Tuple(leftDifference: Diff, rightDifference: Diff) extends Diff
  // etc
}