[libcalamaresui] Drop now-unused sortKey from LocaleLabel

- sortKey is unused
 - add englishLabel for reverse-i18n

src/libcalamaresui/utils/CalamaresUtilsGui.cpp

@@ -269,26 +269,20 @@ LocaleLabel::LocaleLabel( const QString& locale, LabelFormat format )
     //: language[name] (country[name])
     QString longFormat = QObject::tr( "%1 (%2)" );
 
-    QString sortKey = QLocale::languageToString( m_locale.language() );
     QString languageName = m_locale.nativeLanguageName();
+    QString englishName = m_locale.languageToString( m_locale.language() );
     QString countryName;
 
     if ( languageName.isEmpty() )
-        languageName = QString( QLatin1Literal( "* %1 (%2)" ) ).arg( locale, sortKey );
+        languageName = QString( QLatin1Literal( "* %1 (%2)" ) ).arg( locale, englishName );
 
     bool needsCountryName = ( format == LabelFormat::AlwaysWithCountry ) ||
         (locale.contains( '_' ) && QLocale::countriesForLanguage( m_locale.language() ).count() > 1 );
 
     if ( needsCountryName )
-    {
-        sortKey.append( '+' );
-        sortKey.append( QLocale::countryToString( m_locale.country() ) );
-
         countryName = m_locale.nativeCountryName();
-    }
-
-    m_sortKey = sortKey;
     m_label = needsCountryName ? longFormat.arg( languageName ).arg( countryName ) : languageName;
+    m_englishLabel = englishName;
 }
 
 QLocale LocaleLabel::getLocale( const QString& localeName )

src/libcalamaresui/utils/CalamaresUtilsGui.h

@@ -172,6 +172,12 @@ public:
     {
         return m_label;
     }
+    /** @brief Get the *English* human-readable name for this locale. */
+    QString englishLabel() const
+    {
+        return m_englishLabel;
+    }
+
     /** @brief Get the Qt locale. */
     QLocale locale() const
     {
@@ -188,8 +194,8 @@ public:
 protected:
     QLocale m_locale;
     QString m_localeId;  // the locale identifier, e.g. "en_GB"
-    QString m_sortKey;  // the English name of the locale
     QString m_label;  // the native name of the locale
+    QString m_englishLabel;
 } ;