implement sales order to invoice

[metas-ts]

This issue is related to

Todo for developer (besides coding)

• Always make sure the issue is in the correct project lane
• [x] run your test in jenkins e2e
  • [x] https://dashboard.cypress.io/#/projects/5yp4q1/runs/118/specs
  • note that the sales-order and sales-order-to-invoice specs succeeded; for the failed tests, i assumed they are due to temporary low performance on the instance (timeout waiting for window layout)
• [x] get it integrated into master
  • [x] https://github.com/metasfresh/metasfresh-e2e/pull/61

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[metas-ts]

this issue was failing and is currently in integration_defunct/sales/sales_order_to_invoice_spec.js