rename box_array to cell or box

[PythonFZ]

What feature would you like to see added?

project.experiments.ML_273K.box_array
# I think the following attribute names are more convenient than box_array
project.experiments.ML_273K.box
project.experiments.ML_273K.cell

[SamTov]

So if we go with cell we should probably use all the cell vectors. In general our box arrays are name because it is a single array with three numbers. This is quite bad and not descriptive. Cell is also not incredibly descriptive. I would perhaps consider maybe a dataclass called Geometry or something and within it add the properties of the simulation box.