Use and manage the bot key for `fresh_live_data_packet_flatbuffer`

[Quetzal2]

The new fresh_live_data_packet_flatbuffer function can now be "bot agnostic", remembering where each bot is at, by sending it a key value.
The bot index could be used as the key (as proposed here: https://github.com/RLBot/RLBot/blob/5701357231a13cdc182342f16f84e84f336b7ee3/src/main/java/rlbot/cppinterop/RLBotDll.java#L39).

ToDo:

• Where would this key be fed in
• Retrieve and give to the function the current bot's key