Moved rdbms exceptions into the rdbms directory and namespace

catalogue/MysqlCatalogue.cpp

catalogue/SqliteCatalogue.cpp

common/CMakeLists.txt

rdbms/CMakeLists.txt

rdbms/CheckConstraintError.cpp

rdbms/CheckConstraintError.hpp

rdbms/ConstraintError.cpp

rdbms/ConstraintError.hpp

rdbms/PrimaryKeyError.cpp

rdbms/PrimaryKeyError.hpp

rdbms/StmtTest.cpp

rdbms/UniqueError.cpp

rdbms/UniqueError.hpp

rdbms/wrapper/MysqlRset.cpp

rdbms/wrapper/MysqlStmt.cpp

rdbms/wrapper/OcciStmt.cpp

rdbms/wrapper/Postgres.hpp

rdbms/wrapper/PostgresStmtTest.cpp

rdbms/wrapper/SqliteRset.cpp

rdbms/wrapper/SqliteStmt.cpp