[Enhancement]: Field on the StockIssuance object to track difference between Physical Certificate / Digital Certificate / Uncertificated

[jacobyavis]

Description of Enhancement :

For each stock issuance, we should be able to track whether the stock issuance is (1) papered i.e. a Physical Certificate or (2) a Digital Certificate or (3) Uncertificated

Why is this Needed?

There is a desire to be able to track this in the OCX spreadsheet, but we currently do not support this in OCF

Anything else we need to know?

Created while working through the comments sheet attached to issue #507

[jacobyavis]

TWG Notes Sep 12 - We probably want to have a fourth option "Unknown" in cases where it is not known -- in general we probably want this on quite a few of our existing enums as well