Add telemetry and monitoring

[phinner]

Proper telemetry (and/or monitoring) for the different systems, such as:

• maps (ratings)
• players (avg count, new, unique, retention)
• servers (TPS, RAM, GC, spark perhaps ?)

[Maxou-69]

also on map, we can add wave number. On player, number build blocks, number destroyed block, time of connection, time of connection per session.