switch to polling for btcpay payment sessions because btcpay web hooks

are super duper slow

capsulflask/db_model.py

@@ -164,6 +164,17 @@ class DBModel:
     )
     self.connection.commit()
 
+  def list_payment_sessions_for_account(self, email):
+    self.cursor.execute(""" 
+      SELECT id, type, dollars, created
+      FROM payment_sessions WHERE email = %s""", 
+      (email, )
+    )
+    return list(map(
+      lambda x: dict(id=x[0], type=x[1], dollars=x[2], created=x[3]), 
+      self.cursor.fetchall()
+    ))
+
   def consume_payment_session(self, payment_type, id, dollars):
     self.cursor.execute("SELECT email, dollars FROM payment_sessions WHERE id = %s AND type = %s", (id, payment_type))
     row = self.cursor.fetchone()