During attachment upload Pleroma returns a "description" field.
* This MR allows Pleroma to read the EXIF data during upload and return the description to the FE using this field.
* If a description is already present (e.g. because a previous module added it), it will use that
* Otherwise it will read from the EXIF data. First it will check -ImageDescription, if that's empty, it will check -iptc:Caption-Abstract
* If no description is found, it will simply return nil, which is the default value
* When people set up a new instance, they will be asked if they want to read metadata and this module will be activated if so
There was an Exiftool module, which has now been renamed to Exiftool.StripLocation
