Add company data to webhook POST content

We are developing an export feature for invoices to be consumed by a custom on-prem accounting software.

The way we chose to implement this is the automatic webhook on sending an invoice, as the POST request contains all the required information.

As we use multiple companies, the only way to make the receiving webhook aware of the company context is to add a *company_id* query string to the webhook URL.

It would be great if the company attributes were included in thewebhook POST request.