Pull oracle specific changes for reading table column metadata into debezium-core

In OracleConnection#readTableColumn, we specifically need to read the default value from the result-set before any other values due to some quirks with the Oracle JDBC drivers when the default values are stored as types LONG or LONGRAW.

We already handle some quirks specifically with the PostgreSQL JDBC drivers in the impl that is inside JdbcConnection#readTableColumn so there isn't really a reason why we cannot accommodate Oracle's needs in the debezium-core implementation directly.