Need a MIME type

The ASDF file format needs to obtain a MIME media type for accurate referencing, such as `application/asdf`. For example, the MIME format for FITS is `application/fits` with an available explanation on https://mime-type.com/application/fits/. This can then be used in accurate referencing for controlled vocabularies, such as https://cn.dataone.org/cn/v2/formats. See the related addition request at https://github.com/DataONEorg/object-formats/issues/44. The information in the following linked comment may prove useful. https://github.com/zarr-developers/zarr-specs/issues/123#issuecomment-1010210724