Provide per-field template suggestions

@Snator

I ran into a fatal error due to this change, not totally sure if I should post here or fix multiupload_filefield_widget so I'll do both. 🐛 ArgumentCountError: Too few arguments to function image_insert_content(), 3 passed in multiupload_imagefield_widget/multiupload_imagefield_widget.module Active

ArgumentCountError: Too few arguments to function image_insert_content(), 3 passed in multiupload_imagefield_widget/multiupload_imagefield_widget.module on line 125 and exactly 4 expected in image_insert_content() (line 42 of insert/includes/image.inc).
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Don't get me wrong, I appreciate the new life you've given to this module, keep up the good work!