Change of Ownership message

[cookeac]

When working with the Integrity Systems Company group in Australia, we noted there is sometimes a need to record a change of ownership of animals without a movement.
Examples include when animals are purchased or financed on farm, but left to graze there, or when animals change ownership at an auction, but are not yet delivered.

The message has been documented here https://github.com/integritysystemscompany/animal_schema and I propose to copy the documentation here for review, then create a pull request when ICAR members are happy.

[stale]

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