Ungrey Master Backend Name in mythtv-setup settings page

Show the Master Backend Name with a GroupSetting instead
of with a disabled GlobalTextEditSetting.
This makes the help text accessible and it ungreys the label.

mythtv/programs/mythtv-setup/backendsettings.cpp

@@ -24,12 +24,11 @@ static TransMythUICheckBoxSetting *IsMasterBackend()
     return gc;
 };
 
-static GlobalTextEditSetting *MasterServerName()
+static GroupSetting *MasterServerName()
 {
-    auto *gc = new GlobalTextEditSetting("MasterServerName");
+    auto *gc = new GroupSetting();
     gc->setLabel(QObject::tr("Master Backend Name"));
     gc->setValue("");
-    gc->setEnabled(false);
     gc->setHelpText(QObject::tr(
                     "Host name of Master Backend. This is set by selecting "
                     "\"This server is the Master Backend\" on that server."));

mythtv/programs/mythtv-setup/backendsettings.h

@@ -17,7 +17,7 @@ class BackendSettings : public GroupSetting
     TransMythUICheckBoxSetting *m_isMasterBackend   {nullptr};
     HostTextEditSetting        *m_localServerPort   {nullptr};
     HostComboBoxSetting        *m_backendServerAddr {nullptr};
-    GlobalTextEditSetting      *m_masterServerName  {nullptr};
+    GroupSetting               *m_masterServerName  {nullptr};
     IpAddressSettings          *m_ipAddressSettings {nullptr};
     bool                        m_isLoaded          {false};
     QString                     m_priorMasterName;