stx_science_data_lightcurve: Feature for concatenating time profiles of different FITS files

[afbattaglia]

I came across this problem multiple times now and I'm thinking to work on a feature to be included in stx_science_data_lightcurve.

I have a few M class flares and I would like to plot the time profiles using science data. If we use spectrogram data, we clearly see the digital steps. Therefore, one needs to concatenate the different pixel data available for the flares under study. I was thinking to adapt stx_science_data_lightcurve in a way that you can give multiple FITS files and then it concatenates automatically the files before returning the lightcurve structure. However, we also need to check to not have overlapping times.

I plan to work on this in the next few weeks. This Github issue is to keep track of this new feature.