Renamed ConsumedStore to FeedTracker
@Ignore MultipleClientTest for now
Added new EntryConsumer implementation
Updated FeedConsumer
Rewired classes to use new implementation

Changed to accept Links and/or use the new implementation
- FeedConsumerConfiguration
- FeedConsumerScheduler
- EntryConsumerWithMetrics
- FeedConsumerWithMetrics
- PollingActivityHealthCheck
Replaced old implementations
Refactored UnconsumedFeedEntriesFinder (now AvailableFeedEntriesFinder) to add the resource-link to the tracker