Pluggable invoice transmission methods (#5020)

* Flexible invoice transmission

* UI work

* Add peppol and output

* API support

* Profile integration

* Simplify form for individuals

* Remove sent_to_customer usage

* more steps

* Revert "Bank transfer: Allow to send the invoice direclty to the accounting department (#2975)"

This reverts commit cea6c340be.

* minor fixes

* Fixes after rebase

* update stati

* Backend view

* Transmit and show status

* status, retransmission

* API retransmission

* More fields

* API docs

* Plugin docs

* Update migration

* Add missing license headers

* Remove dead code, fix current tests

* Run isort

* Update regex

* Rebase migration

* Fix migration

* Add tests, fix bugs

* Rebase migration

* Apply suggestion from @luelista

Co-authored-by: luelista <weller@rami.io>

* Apply suggestion from @luelista

Co-authored-by: luelista <weller@rami.io>

* Apply suggestion from @luelista

Co-authored-by: luelista <weller@rami.io>

* Apply suggestion from @luelista

Co-authored-by: luelista <weller@rami.io>

* Apply suggestion from @luelista

Co-authored-by: luelista <weller@rami.io>

* Make migration reversible

* Add TransmissionType.enforce_transmission

* Fix registries API usage after rebase

* Remove code I forgot to delete

* Update transmission status display depending on type

* Add testmode_supported

* Update src/pretix/static/pretixbase/js/addressform.js

Co-authored-by: luelista <weller@rami.io>

* Update src/pretix/static/pretixbase/js/addressform.js

Co-authored-by: luelista <weller@rami.io>

* Update src/pretix/static/pretixbase/js/addressform.js

Co-authored-by: luelista <weller@rami.io>

* New mechanism for non-required invoice forms

* Update src/pretix/base/invoicing/transmission.py

Co-authored-by: luelista <weller@rami.io>

* Declare testmode_supported for email

* Make transmission_email_other an implementation detail

* Fix failing tests and add new ones

* Update src/pretix/base/services/invoices.py

Co-authored-by: luelista <weller@rami.io>

* Add emails to email history

* Fix comma error

* More generic default email text

* Cleanup

* Remove "email invoices" button and refine logic

* Rebase migration

* Fix edge case

---------

Co-authored-by: luelista <weller@rami.io>

src/tests/api/test_order_create.py

@@ -436,7 +436,9 @@ def test_order_create_simulate(token_client, organizer, event, item, quota, ques
             'vat_id': '',
             'vat_id_validated': False,
             'internal_reference': '',
-            'custom_field': None
+            'custom_field': None,
+            'transmission_type': 'email',
+            'transmission_info': None,
         },
         'positions': [
             {
@@ -590,6 +592,39 @@ def test_order_create_invoice_address_optional(token_client, organizer, event, i
             o.invoice_address
 
 
+@pytest.mark.django_db
+def test_order_create_invoice_address_transmission_type_validation(token_client, organizer, event, item, quota, question):
+    res = copy.deepcopy(ORDER_CREATE_PAYLOAD)
+    res['positions'][0]['item'] = item.pk
+    res['positions'][0]['answers'][0]['question'] = question.pk
+    res['invoice_address'] = {
+        "is_business": True,
+        "company": "This is my company name",
+        "name": "John Doe",
+        "name_parts": {},
+        "street": "",
+        "zipcode": "",
+        "city": "Test",
+        "country": "FR",
+        "internal_reference": "",
+        "vat_id": "",
+        "transmission_type": "it_sdi",
+        "transmission_info": {
+            "transmission_it_sdi_pec": "foobar@pec.it",
+            "transmission_it_sdi_recipient_code": "1234567",
+        },
+    }
+    resp = token_client.post(
+        '/api/v1/organizers/{}/events/{}/orders/'.format(
+            organizer.slug, event.slug
+        ), format='json', data=res
+    )
+    assert resp.status_code == 400
+    assert resp.data == {"invoice_address": {
+        "transmission_type": ["The selected transmission type is not available for this country or address type."]
+    }}
+
+
 @pytest.mark.django_db
 def test_order_create_sales_channel_optional(token_client, organizer, event, item, quota, question):
     res = copy.deepcopy(ORDER_CREATE_PAYLOAD)