DRILL-7706: Implement Drill RDBMS Metastore 1. Fix issue with undeterministic execution of batch update / delete statements, now they will b…
DRILL-7706: Implement Drill RDBMS Metastore1. Fix issue with undeterministic execution of batch update / delete statements, now they will be executed in the same order as they were added.2. Abstracted Metastore common test classes to be used by different Metastore implementations.3. Added drill-metastore-override-example.conf with example of Drill Metastore configuration.4. Replaced list of metadata types which are required to be passed during read / write operations with set to avoid possible duplicates.5. Add RDBMS Metastore implementation, README.md and unit tests.