Optionally return raw value for unsupported column types

Currently, when encountering columns of a type not supported yet by Debezium, a warning will be raised and that column will not be part of emitted change messages. So consumers have no way of getting hold of such values, also if they actually might be able to interpret the raw value themselves. In such case the only way is to do a new snapshot after the connector has been updated to support such new column types, which may not always be desirable.

Hence we should have an option – defaulting to not being enabled – which would emit the raw value as obtained from the database, as part of change messages. A warning should still be raised in such case upon first encounter.

Naturally, clients are that way dependent on the internal representation of that type and there are no guarantees on stability of it whatsoever, but when used cautiously, it still may serve as a useful loophole in some cases, until a type is supported officially by Debezium.