Housekeeping in VizFwk in preparation for introducing support for QOpenGLWidget and Qt6
* Adjusted unit tests to changes in source code
* Use Qt5 as default and removed copying of Qt DLLs
* Removed support for Qt4
* Removed the CVF_OPENGL_ES define. If we ever want to re-introduce support fro OpenGLES/Angle it should be handled differently.
*Added include of <locale.h>
* Added target for running Glsl2Include in order to build cvfShaderSourceStrings.h
* Removed all usage of CVF_USING_CMAKE
* Removed visual studio project files
- Update the minimum required CMake version to 3.15 for Fwk folders
that might be used as top level projects.
- Remove the minimum required CMake version from projects that is just
included from other top level projects.
Since version 3.19 CMake has been warning that CMake versions below 3.5
is deprecated and support will be removed in the future. This will
silence those warning.
By removing the minimum required version check from projects that is not
intended as top level projects we avoid redundant checks and simplifies
future maintenance.
Closes#10957
