Implement payment backends and interaction

Advances #3 (closed)

aleksis/apps/tezor/apps.py

@@ -49,4 +49,15 @@ class DefaultConfig(AppConfig):
                 "endpoint": "https://api.paypal.com",
             })
 
+        if prefs["payments__pledge_enabled"]:
+            variants["paypal"] = ("djp_sepa.PaymentPledgeProvider", {
+            })
+
+
+        if prefs["payments__sdd_creditor_identifier"]:
+            variants["paypal"] = ("djp_sepa.DirectDebitProvider", {
+                "creditor": prefs["payments__sdd_creditor"],
+                "creditor_identifier": prefs["payments__sdd_creditor_identifier"],
+            })
+
         return variants