Change the input parameter `country_iso_code` and `bounding_box` of `import_from_postgis` into one parameter `import_region`
It seems useful to me to unify the two mutual exclusive input parameters
bounding_box of the
import_from_postgis into one parameter
import_region. Thew user can either provide a three-letter ISO code or a dictionary of the four bounding-box coordinates. The function code will determine which type of region definition is provided by the user. Currently, the user has to provide one of the two parameters, which requires an extra check if one and only one has been provided. With only one parameter, the user interface becomes simpler and easier to use. Also, this change can be propagated to exposure-share to make it more versatile.