Log warning when table/column name exceeds maximum allowed by LogMiner

Oracle 12.2 and Oracle 19.x both have a limitation that object names cannot exceed 30 characters or else LogMiner will report the redo entry as UNSUPPORTED.

Users may be confused when events are not emitted for tables that have this condition and may think there is a problem with the connector. To remedy this use case, we should log a warning at the start of streaming indicating whether we've encountered a table or column name that exceeds this limit.