Class TerminalStripLayoutPattern can be save/load from xml

Add a new class TerminalStripLayoutPatternXml used to
save / load a TerminalStripLayoutPattern class into a xml.

Also create the namespace QETSVG used to read/write some
svg element / attribute to xml. This class is used by the
class TerminalStripLayoutPatternXml.

sources/svg/qetsvg.h

@@ -0,0 +1,51 @@
+/*
+    Copyright 2006-2025 The QElectroTech Team
+    This file is part of QElectroTech.
+
+    QElectroTech 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 2 of the License, or
+    (at your option) any later version.
+
+    QElectroTech 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 QElectroTech. If not, see <http://www.gnu.org/licenses/>.
+*/
+#ifndef QETSVG_H
+#define QETSVG_H
+
+#include <QDomElement>
+
+class QDomDocument;
+class QPointF;
+class QRect;
+
+/**
+ * @namespace QETSVG
+ * @brief the QETSVG namespace provide function read and write svg.
+ * Some function work on xml element (ex rect) and some other
+ * work on attribute of an element (ex x)
+ */
+namespace QETSVG
+{
+    QDomElement rectToElmt(const QRect &rect, QDomDocument &parent_document);
+    QRect rectFromElmt(const QDomElement &xml_element);
+
+    void yToAttribute(const qreal &y, QDomElement &xml_element);
+    qreal yFromAttribute(const QDomElement &xml_element, const qreal &def_value=0);
+
+    void heightToAttribute(const qreal &height, QDomElement &xml_element);
+    qreal heightFromAttribute(const QDomElement &xml_element, const qreal &def_value=10);
+
+    void rToAttribute(const qreal &r, QDomElement &xml_element);
+    qreal rFromAttribute(const QDomElement &xml_element, const qreal &def_value=1);
+
+    void pointsToAttribute(const QVector<QPointF> &points, QDomElement &xml_element);
+    QVector<QPointF> pointsFromAttribute (const QDomElement &xml_element);
+}
+
+#endif // QETSVG_H