Introducing the MagneticNotificationRowManager.

The manager handles the translation of ExpandableNotificationRows so
that they implement a magnetic attachment to each other. It also handles
the logic of triggering snapping and detaching animations as well as
haptics.

This is the first of a series of two changes. The second change
integrates the manager with the relevant components that handle
notification swipes.

Flag: NONE The usage of the manager and its capabilities are flagged by
  the change that integrates with the NSSL controller
Test: MagneticNotificationRowManagerImplTest
Test: NotificationTargetsHelperTest
Bug: 390179908
Change-Id: Idd915240e1e7543233b0f3aa9f53607feb7e224b