ENH: Allow users to have a CMakeUserPresets.json file

CMake now provides a mechanism for defining preset confiurations
for selecting and building based on user preferences.

CMakeUserPresets.json should NOT be checked into a version control system.

CMakePresets.json may be tracked in git, but
CMakeUserPresets.json should be added to the .gitignore.

.gitignore

@@ -43,3 +43,6 @@ CMakeLists.txt.user*
 
 # Ignore testing temporary files
 Testing/Temporary/
+
+# CMake user presets
+CMakeUserPresets.json