Added form annotation builder factory

Two outstanding items for this pull request:

1. What is the best method to get it into the default service locator config?
2. Should the factory support adding custom annotations and annotation listeners to the builder?
This was done to stay in keeping with the rest of the framework; my usual preference for this is to add the FQCN in the invokables/factories array and add an additional alias in the aliases section. Let me know which option (of the 3) you prefer and I'll update.