Add default chest tracker binding

[Erimelowo]

VRChat warns about chest tracker bindings when starting up.

We can add default bindings for VRChat:

  "default_bindings": [
    {
      "app_key": "438100",
      "binding_url": "vrchat_bindings_slimevr_chest.json"
    }
  ]

in a slimevr_chest_bindings.json file that we need to make.

Then in TrackerDevice.cpp

if (isChestTracker) GetDriver()->GetProperties()->SetStringProperty(props, vr::Prop_InputProfilePath_String, "{slimevr}/input/slimevr_chest_bindings.json");

We might also be fine just applying the default binding for any non-hand/controller tracker instead of just chest.