Create a media file object
Arguments
- location
 An absolute or relative URL to the file.
- title
 The title of the multimedia record.
- media_type
 The media type as defined in RFC 2045.
- medium
 A value from
val_medium_types(). If "OTHER" is selected then a@medium_phrasemust be given. This should describe the original medium from which it was derived. So if it is a digital image scanned from a physical photograph, it should be "PHOTO" instead of "ELECTRONIC".- medium_phrase
 A free text description of the medium. This is mandatory if
@mediumis "OTHER".- media_alt
 A named vector of the media in alternative media forms, c(form = location)