Implement Barrage ColumnConversionModes

[nbauernfeind]

We added serialization options to optionally convert barrage-unfriendly columns to strings, java serialization, or to throw errors. This is feature is orthogonal to custom type support which upgrades an unfriendly column to a friendly one.

DoPut/DoPush must refuse to allow a client to request them to do deserialization (maybe an enable-able feature?).

See: https://github.com/deephaven/barrage/blob/main/format/Barrage.fbs#L92