[Enhancement]: Add support for 'balance cancellation' when doing a Transfer

[jacobyavis]

Description of Enhancement :

The schema for Stock Transfer does not support a situation where there's a partial transfer with the balance cancelled. Currently the only way to do this would be to issue a balance certificate then subsequently cancel it. The problem with this is platforms that support this will not have a security_id to reference for the temp balance certificate.

Why is this Needed?

To properly represent a partial transfer+ balance cancellation transaction (such as is possible in Shareworks), since TX_STOCK_TRANSFER expects all shares to go to new security_ids (either transferee certificates or a balance certificate)

[pjohnmeyer]

TWG: At issue here is the fact that transfers are considered "terminal" transactions in OCF.

From https://github.com/Open-Cap-Table-Coalition/Open-Cap-Format-OCF/blob/86b1229088c8a69ba58547c07dfb06401bb2e2db/docs/explainers/TraversingTransactions.md:

6. Transfer - transactions composed of Transfer - which includes StockTransfer, WarrantTransfer, PlanSecurityTransfer and ConvertibleTransfer - transactions must link to the security_id of the original issuance the transferred securities were issued as a part of. This transfer can be in whole or in part, and it can be to a single new issuance or to multiple new issuances. If the transfer is in-part, any remaining securities must be issued with a new security_id which should be referred to as the balance_security_id. The security_ids of the resulting issuances to the transferees should be recorded in an array in the resulting_security_ids field.

In the case as @jacobyavis describes, if we follow this documentation, the solution requires creating an issuance that was never actually issued, and then cancel / retract it. That seems misleading.

The approach in #486 would resolve this issue. We could also choose to say that partial transfers are not terminal transactions, which would allow the sequence to be ISSUANCE, TRANSFER, CANCEL on the initial security.

@pjohnmeyer to refer this issue to the law firm working group to determine two things:

1. Does this really happen, or is this, as Jake put it, a "Shareworks-ism"?
2. If it does, how is it mechanized in reality?

[pjohnmeyer]

This is on the agenda for LFWG Monday 6 May.

[pjohnmeyer]

This remains an open question as it was not discussed at yesterday's call.

[jacobyavis]

This idea has been largely shut down -- not a standard practice by any means