Refactor WiFi code around XL setup

Major:
- move SetupWizard-related codes to WifiSettingsForSetupWizardXL as
  much as possible
- stop using Preference for configurinig wifi network. We use
  WifiConfigUiForSetupWizardXL instead, which is base on a bare View.

Minor:
- change button handling code expecting better readability.
- hide Detail button.
- modify strings a bit.
- add logs

Bug: 3175016
Change-Id: I5b29917af73aac6a82e13ba846a9d5085f9bd523

src/com/android/settings/wifi/WifiDialog.java

@@ -54,7 +54,7 @@ class WifiDialog extends AlertDialog implements WifiConfigUiBase {
         mView = getLayoutInflater().inflate(R.layout.wifi_dialog, null);
         setView(mView);
         setInverseBackgroundForced(true);
-        mController = new WifiConfigController(this, mView, mAccessPoint, mEdit, mListener);
+        mController = new WifiConfigController(this, mView, mAccessPoint, mEdit);
         super.onCreate(savedInstanceState);
     }