Updated version number in POM to reflect new changes as being part of the 3.1.1 release

GCP-10542

Reviewer : Darla Grace Ani
Added check for existing email in Person table

BMS-119

Reviewer: Daniel Villafuerte
Cleanup: Removed org.generationcp.middleware.service.ServiceFactory class which was largely a duplicate of org.generationcp.middleware.manager.ManagerFactory and was only used in tests. ManagerFactory is sufficient to create service impl classes.
Sync: Merge branch 'master' into 'BMS-90-merged-db'