Design: Deleting Invoices

[jniles]

This issue covers the design for deleting Invoices using the proposal described in #2044.

Design
Deleting invoices will be performed from the Invoice Registry and the Posting Journal (via the transaction edit modal). It is not allowed on posted records. A deleted invoice will remove the lines from the posting_journal, invoice, invoice_item, invoice_billing_service, and invoice_subsidy. It will also remove the record_uuid from the document_map.

There are some conditional rules on this operation:

1. If the invoice has been posted, it cannot be deleted. The only way to reverse a posted record is by using a reversing voucher.
2. If the invoice has a referencing transaction, it cannot be deleted. This is most likely a voucher that is reversing the invoice or a cash payment against the invoice.

The steps to implement this are:

1. Create a routing function from HTTP DELETE /transactions/:uuid that will determine if the transaction is a cash payment, voucher, or invoice.
2. Create the safelyDeleteInvoice(uuid) in the finance/patientInvoice.js. module.
3. Write the SQL logic to determine if the invoice should be deleted as described in the above rules.

[DedrickEnc]

@jniles
Why not HTTP DELETE /invoices/:uuid as route?

[jniles]

It makes it much easier to write a single controller on the client.

[jniles]

Closed in #2188.