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/daemon.py

@@ -386,7 +386,7 @@ class Daemon(Logger):
             return
         if storage.get_action():
             return
-        wallet = Wallet(storage)
+        wallet = Wallet(storage, config=self.config)
         wallet.start_network(self.network)
         self._wallets[path] = wallet
         self.wallet = wallet