api/oracledb library

1. oraffi package
2. documentation
3. api/oracledb.dart

oraffi package

1. Libraries
2. api/connection
3. api/connection_pool
4. api/lob
5. api/oracledb
6. api/out_param
7. api/resultset
8. api/statement
9. api/variable
10. config/oracle_config
11. dpi_oracle
12. exceptions/oracle_exception
13. oraffi
14. utils/library_loader
15. utils/memory_manager