JWST light curve handling

[abigailStev]

We want to be able to handle JWST light curves when the data come in!

• Find example JWST data
• See what format the light curves will be in
• Play around with how to best turn that into a Lightcurve object in Stingray
• Write a tutorial in jupyter notebooks for doing exactly this, put in notebooks repo
• Perhaps write helper method for io.py if it has a quite complicated step?
• Add a link to that notebook in the dataexplo.rst docs file