Remove PerformanceMonitor and update references to PerformanceProfiler

- Deleted the PerformanceMonitor implementation and header files as functionality has been fully integrated into gfx::PerformanceProfiler.
- Updated all relevant source files to replace PerformanceMonitor and ScopedTimer with their gfx counterparts, ensuring consistent performance monitoring across the application.

src/cli/z3ed.cmake

@@ -31,7 +31,6 @@ add_executable(
   app/rom.cc
   app/core/project.cc
   app/core/asar_wrapper.cc
-  app/core/performance_monitor.cc
   ${FILE_DIALOG_SRC}
   ${YAZE_APP_EMU_SRC}
   ${YAZE_APP_GFX_SRC}