Handle infe items of type "uri "

[dukesook]

infe items of type "uri " contain customized metadata The uri_type is a 16-byte key that indicates how to parse the raw out_data A list of some registered uri keys can be found here: https://registry.smpte-ra.org/view/published/groups_view.html

Added API Functions:

1. heif_context_add_uri_metadata()
2. heif_image_handle_get_metadata_uri_type()