Need to allow metacat admin to set default mime type
the metacat servlet does it's best to determine the mime type of the data entity
being served. However, entities that are stored on the local filesystem with a
name in the form of prefix.1.1 don't give the servlet any clues as to the mime
type based on the file ending. As a last resort, metacat sets the default mime
type to application/octet-stream, which results in a 'download' dialog over the
web, rather than attempting to render the data file (even text/plain).
This may be desired, but some metacat admins may want text files to render
preferentially, or other file types. It seems that there needs to be a mapping
between eml dataFormat fields that hold the equivalent of a mime type (or it's
surrogate), and the true mime type name used to set the HTTP CONTENT_TYPE
header. The mapping shouldn't be schema dependent, rather, when a schema is
registered in metacat, the mapping should be registered as well.