Create Database Table mapping release to puid that is populated by a trigger on new puids

Rob, a while ago we discussed doing this to improve the speed of building the search index so that it could easily get all the puids for a release without having to access track/recording/puid tables.

We tried to improve the speed of indexing without doing this, this improved things a bit for you but actually made things worse in my setup, and the sensible thing to do is add this table it will improve the building of the index significantly.