Roadmap to create the integration app

[roquegv]

The goal is to build an app that export data from ERPNext in a format that is specific to BMD.
The technical specifications are detailed in the BuErf document:

• German:
  BuErf Import - Import von Buchungen.pdf
  English:
  BuErf Import - Import von Buchungen.de.en.pdf

We have a document which describe the Mapping from ERPNext's fields to BMD fields: https://docs.google.com/document/d/1mSQL0LLhkhShy7U983T_o6fGy8ZfcjbFf04n7Y1HnMQ/edit.

TODOs:

• Create a Frappe app
• Add new field satzart (select field, default = 0) in Sales Invoice and Purchase Invoice.
• Create a Single Doctype which will serve as a generator of the CSV files. This will have some filters (start date, end date) and a child table to show the list of Sales Invoices (or Purchase Invoices) with the appropriate fields. It also allow to download the CSV file.