Fix Stephan 2021 ROIs latitude and longitude outside the bounding box

Closes #25

Recompute the latitude and longitude of Ganymede and Callisto ROIs based on their bounding box provided in Stephan et al. 2021 (PSS) supplementary tables. The new maps looks like this:

A close up look category by category can be found here:

• Stephan_2021_PSS-Callisto_ROIs-Categories.pdf
• Stephan_2021_PSS-Ganymede_ROIs-Categories.pdf