Changes to be able to convert the .pt model to ONNX and TensorRT formats

[Hyrtsi]

Greetings,

I have created this PR merely to present the changes necessary to be able to use the pre-trained ELG model in TensorRT code. I also added some details to README about installation and software requirements as they were lacking some details.

My PR doesn't necessarily have to be merged on swook/GazeML but I wanted to leave this here to save somebody else time if they want to do the things I did.