[libcalamares] Stub of class for TimeZone model management

- Intent is to move out of locale module

src/libcalamares/locale/TimeZone.h

@@ -0,0 +1,69 @@
+/* === This file is part of Calamares - <https://github.com/calamares> ===
+ *
+ *   Copyright 2019, Adriaan de Groot <groot@kde.org>
+ *
+ *   Calamares is free software: you can redistribute it and/or modify
+ *   it under the terms of the GNU General Public License as published by
+ *   the Free Software Foundation, either version 3 of the License, or
+ *   (at your option) any later version.
+ *
+ *   Calamares is distributed in the hope that it will be useful,
+ *   but WITHOUT ANY WARRANTY; without even the implied warranty of
+ *   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+ *   GNU General Public License for more details.
+ *
+ *   You should have received a copy of the GNU General Public License
+ *   along with Calamares. If not, see <http://www.gnu.org/licenses/>.
+ */
+
+#ifndef LOCALE_TIMEZONE_H
+#define LOCALE_TIMEZONE_H
+
+#include <QString>
+
+namespace CalamaresUtils
+{
+namespace Locale
+{
+
+/** @brief A pair of strings, one human-readable, one a key
+ *
+ * Given an identifier-like string (e.g. "New_York"), makes
+ * a human-readable version of that and keeps a copy of the
+ * identifier itself.
+ *
+ * This explicitly uses const char* instead of just being
+ * QPair<QString, QString> because there is API that needs
+ * C-style strings.
+ */
+class CStringPair
+{
+public:
+    explicit CStringPair(const char *s1);
+    CStringPair(CStringPair&& t);
+    CStringPair(const CStringPair&) = delete;
+    ~CStringPair();
+
+private:
+    const char* m_human = nullptr;
+    const char* m_key = nullptr;
+};
+
+/// @brief A pair of strings for timezone regions (e.g. "America")
+class TZRegion : public CStringPair
+{
+public:
+    using CStringPair::CStringPair;
+};
+
+/// @brief A pair of strings for specific timezone names (e.g. "New_York")
+class TZZone : public CStringPair
+{
+public:
+    using CStringPair::CStringPair;
+};
+
+}
+}
+
+#endif  // LOCALE_TIMEZONE_H