Viewable queue exposed in Data Application Routes

[scasplte2]

Summary

This PR introduces a ViewableQueue trait and implementation in order to expose pending data updates via a GET public HTTP route. This work is motivated to provide a "mempool" equivalent at the metagraph layer while maintaining atomicity, minimizing changes to existing usages of currency.l1.modules.Queues, and reusing the available API of Cats standard Queue.

Additionally, smaller changes were incorporated to facilitate encoding and decoding of DataUpdates and HttpSuite was updated to MutableIOSuite as the override of Res and def sharedResource were causing compilation errors.

Changes

• Updated currencyL1 project definition to include test dependencies
• Updated usages of dataUpdates: Queue -> ViewableQueue
• Added GET route at /data to return the latest view of pending updates
• Added MockDataApplicationService and ...State to facilitate testing
• Added EntityEncoder[F, Signed[DataUpdate]] in DataApplication package
• Updated HttpSuite from SimpleIOSuite -> MutableIOSuite

Testing

• Added ViewbleQueueSuite unit tests
• Added DataApplicationRoutesSuite integration tests cases handling
  • empty queue
  • single element
  • multiple elements

[marcinwadon]

@scasplte2 please remember to squash your commits into a single atomic change.