* CMake: Remove dead CODE_HEADER_FILES variable
* CMake: Remove dead COMMAND_CODE_HEADER_FILES and COMMAND_MOC_SOURCE_FILES
* CMake: Remove dead MOC_SOURCE_FILES and FORM_FILES_CPP references
* CMake: Remove dead HEADER_FILES reference
* CMake: Delete unused CustomPCH.cmake superseded by target_precompile_headers
Move the QMessageBox-displaying helper out of the logging utility into a
dedicated UI class. RiaLogging.h no longer pulls QMessageBox/QWidget into
the ~270 files that include it. Behavior is preserved: showError displays
the dialog when running interactively (and not under regression tests),
then forwards the text to RiaLogging::error.
* Refactor interface to PdmObjectHandle and PdmFieldHandle
Return objects instead of passing in structures as parameters
* Add nodiscard to several functions
* Remove redundant this->
* Rename to ptrReferencedObjectsByType