Owner cannot be updated, only set during creation

[VMelnalksnis]

Describe the bug
None of the Update.sql queries actually set the onwer_id column, so it's not possible to update the owner.

To Reproduce
Steps to reproduce the behavior:

1. Add owner_id = @OwnerId to any Update.sql file
2. See that access control tests fail because owner has been changed and the original owner cannot read the entities

Expected behavior
The owner is updated as any other column

[VMelnalksnis]

It's been some time, so I guess I've forgotten what I've written; probably have to add some documentation regarding this. Anyway, looks like like the owner can only be updated for 'root' entities - accounts, transactions and loans. For all other entities it's only possible to set it during creation (though I'm not sure if that should even be possible). Since the access is inherited from root entities, it can be modified via those.