Add changes file for Qt 5.10.0

Change-Id: Ia25344ea00a919d5066814101b6f808964837944
Reviewed-by: Leena Miettinen <riitta-leena.miettinen@qt.io>

dist/changes-5.10.0

+Qt 5.10 introduces many new features and improvements as well as bugfixes
+over the 5.9.x series. For more details, refer to the documentation included
+in this distribution. The documentation is also available online:
+
+https://doc.qt.io/qt-5/
+
+The Qt version 5.10 series is binary compatible with the 5.9.x series.
+Applications compiled for 5.9 will continue to run with 5.10.
+
+Some of the changes listed in this file include issue tracking numbers
+corresponding to tasks in the Qt Bug Tracker:
+
+https://bugreports.qt.io/
+
+Each of these identifiers can be entered in the bug tracker to obtain more
+information about a particular change.
+
+****************************************************************************
+*                               Qt 5.10.0 Changes                          *
+****************************************************************************
+
+ - Updated documentation for Qt for VxWorks.
+ - Clarified on where Qt license files are stored locally.
+ - Documented dynamic language changes in Qt Quick applications.
+ - Added examples/demos: Qt Cluster Demo, Coffee.
+ - Fixed several instances of missing, incorrect, or obsolete information.