PProv: Implement detection of wallets such as Google Pay and Apple Pay (#3444)

Co-authored-by: Richard Schreiber <schreiber@rami.io>

src/pretix/base/payment.py

@@ -78,6 +78,16 @@ from pretix.presale.views.cart import cart_session, get_or_create_cart_id
 logger = logging.getLogger(__name__)
 
 
+class WalletQueries:
+    APPLEPAY = 'applepay'
+    GOOGLEPAY = 'googlepay'
+
+    WALLETS = (
+        (APPLEPAY, pgettext_lazy('payment', 'Apple Pay')),
+        (GOOGLEPAY, pgettext_lazy('payment', 'Google Pay')),
+    )
+
+
 class PaymentProviderForm(Form):
     def clean(self):
         cleaned_data = super().clean()
@@ -436,6 +446,19 @@ class BasePaymentProvider:
         d['_restrict_to_sales_channels']._as_type = list
         return d
 
+    @property
+    def walletqueries(self):
+        """
+        .. warning:: This property is considered **experimental**. It might change or get removed at any time without
+                     prior notice.
+
+        A list of wallet payment methods that should be dynamically joined to the public name of the payment method,
+        if they are available to the user.
+        The detection is made on a best effort basis with no guarantees of correctness and actual availability.
+        Wallets that pretix can check for are exposed through ``pretix.base.payment.WalletQueries``.
+        """
+        return []
+
     def settings_form_clean(self, cleaned_data):
         """
         Overriding this method allows you to inject custom validation into the settings form.