#3 Allow Merging Duplicate Certifications

It is currently easy to accidentally create minor variations of a certification tag such that it is obvious that all of these should be merged to a single representation. While it is relatively easy to merge these with SQL, it would be better to provide an interface to do that from within Typica.

In addition to merging existing certifications, wherever this functionality ends up might also be a good place to allow deleting certifications. Merge and delete needs to ask for confirmation (maybe including how many records proposed changes will affect) as this will not be implemented in a way that is easy to undo.