Transition issue with Benchmark 2 and new event system

[ahmadbky]

Unlike the current Benchmark 2, this feature doesn't make a distinct insert of the maps UIDs in the database to separate the leaderboard. Thus, the integrated maps of Benchmark 2 in this feature aren't the original but their benchmark versions (with *_benchmark UIDs). We need a way to tell what concrete map is the original in the context of the event.

Also for sustainability reasons, we need to get rid of the hardcoded mechanisms used in the API to manage the Benchmark 2 event.