Conn 1390:Fix for not allowing to add duplicate domain

1. Added logic for not to allow adding / updating duplicate domains.Updated related DirectDomainBean.java and other related DAO's and Impl files.
2. Created CreateDomainException class to Instantiate new create domain exception.
3. Updated domaincreatedialog.xhtml, domaineditdialog.xhtml to fix dialogue window refresh issue.
4. Updated configdb.sql,nhincdb.sql and nhincdb_oracle.sql to add unique constraint on domain name in domain table.

Same comment as above.