Registry refactor

    - Moving InstanceInfo related classes to a new package (to help with moving registries into core)
    - Moving Sourced Registry and Preservable Registry to eureka-core
    - Using a persistent preservable registry in eureka-client. During interest channel
      failover, the registry content is sent to the eviction queue.
    - Fixed a big with the EvictionSubscriber that drops one item when going into self preservation
    - Cleaned up close() and shutdown() behaviours for a bunch of classes
    - Test updates and fixes
    - Fix integTest shutdown