config: no longer singleton. it is passed to Wallet.__init__

The few other cases that used SimpleConfig.get_instance() now
either get passed a config instance, or they try to get a reference
to something else that has a reference to a config.
(see lnsweep, qt/qrcodewidget, qt/qrtextedit)

electrum/plugins/trustedcoin/trustedcoin.py

@@ -261,9 +261,9 @@ class Wallet_2fa(Multisig_Wallet):
 
     wallet_type = '2fa'
 
-    def __init__(self, storage):
+    def __init__(self, storage, *, config):
         self.m, self.n = 2, 3
-        Deterministic_Wallet.__init__(self, storage)
+        Deterministic_Wallet.__init__(self, storage, config=config)
         self.is_billing = False
         self.billing_info = None
         self._load_billing_addresses()