Reward mod

[neverix]

• Adds a system for getting rewards
• Each frame, the reward attribute is set as a global variable from a client script
• This enables eventually creating custom rewards and decouples it from the game code
• Unlike the previous PR, this version does not have a server-side component. It can be added back in later

To do

This PR is a Work in Progress

• Implement Lua mod
• Read the player reward metadata in C++
• Get it to game.cpp so it can be sent to the Recorder
• Read reward from Python

How to test

hacking_testing/test_loop.py

[Rabbidon]

lgtm