Animate provisional and final score reveal in mini leaderboard

[callmekatootie]

MERGE ONLY IF leaderboard api is updated to return finalDetails attribute for each review, which is the final scores

  "finalDetails": {
    "aggregateScore": 89,
    "testsPassed": 80,
    "totalTestCases": 100
  }

2 new env variables added:

LEADERBOARD_REVEAL_DELAY - that controls how long AFTER final scores are available should the UI display them (like the hold period)
DEV_LEADERBOARD_REVEAL_DELAY that controls the time, when the UI decides to show the final scores, in which each member score is revealed

First LEADERBOARD_REVEAL_DELAY comes into play and then DEV_LEADERBOARD_REVEAL_DELAY