Added connection pooling on core, added ObsCore uytpe and ucd on XML model, added ObsCore optional columns

Added UsersManagement page for admin, added 'UCD Rebuild' functionality based on CDS web services, refactoring, removed ConversationScoped in favour of DeltaSpike WindowScoped, set version number to 1.1.0

Manage all without JPA; move some application logic into the datalayer (in order to rename it as TapSchemaManagerAPI); started management of multiple versions of TAP_SCHEMA added documentation