camera2: Add re-usable data types for camera metadata key/values

Adds new types to public API:
* ColorSpaceTransform
* Range<T>
* SizeF (android.util)
* MeteringRectangle

Minor changes to:
* Size (docs and move to android.util)
* Preconditions (@hide)

Adds helper class:
* HashCodeHelpers

Change-Id: Ied6749a19234f3af9da838f365f8d68d90251aaf