Improved Handling of Green Coffee Certifications

[N3Roaster]

While it is currently possible to specify that a coffee has some certification on purchase, most third party certifications carry additional information such as the certifying agency, additional identifying information, and so on. It should be possible to enter this information and also update it if the information is not available at the time of purchase. The ability to save a scan of the certification documentation and recall this from the database would also be helpful. All of this information needs to be better available through reporting interfaces.

[N3Roaster]

This should subsume #72.