View an authority record by id

View an authority record by id

Suggested by cataloging staff, there is no way to view an authority
record directly by id. The 'Manage Authorities' interface does not
allow retrieval of an authority record by id. This branch
leverages Supercat to display an authority as marctxt in the staff
client. Staff are ambivalent about the right-click interface for
viewing authorities in the marc editor (which could be a separate
issue), so they feel this is important. Primary use case is to
quickly view authority using id indicated in $0 subfield. Outstanding
question -- should this really load the authority in the marc editor?

Signed-off-by: Mark Cooper <markchristophercooper@gmail.com>