#1254 Create command to see recently logged in players

- Create datasource method to fetch most recent players by last login date
- Add command to view last logged in players

src/main/java/fr/xephi/authme/datasource/CacheDataSource.java

@@ -263,6 +263,11 @@ public class CacheDataSource implements DataSource {
             .collect(Collectors.toList());
     }
 
+    @Override
+    public List<PlayerAuth> getRecentlyLoggedInPlayers() {
+        return source.getRecentlyLoggedInPlayers();
+    }
+
     @Override
     public void invalidateCache(String playerName) {
         cachedAuths.invalidate(playerName);