[do not merge] shrink memory layout of garagedoor to the tight required minimum

[samuelgruetter]

This is just to demo that the end-to-end garagedoor theorem still holds if we shrink the memory requirements to the required minimum. This is a fun experiment to mention in an evaluation section, but I would not merge it, because any future change that increases memory usage, no matter by how little, would break the end-to-end theorem, whereas with the current memory layout, we have some slack, which I think we should keep.