Save data to csv

[RemDelaporteMathurin]

After running a simulation, users should be able to download the data as a csv file in the results tab

[RemDelaporteMathurin]

@tasnimxvi this is how we access the data from the pathsim.Scope objects: https://github.com/tasnimxvi/fuel-cycle-sim/blob/b14b72a643ddf2e9a6ebf0eb1212bdf0c659e67f/src/backend.py#L478-L483

Ignore the plotting calls but we could then couple that to np.savetxt(...) to save it to CSV somewhere (maybe the downloads folder by default?)