Consolidate shared HALs and isolate HAL compile (#11552)

Marlin/src/HAL/HAL_DUE/DebugMonitor_Due.cpp

@@ -26,8 +26,8 @@
 #include "../../core/serial.h"
 #include <stdarg.h>
 
-#include "../backtrace/unwinder.h"
-#include "../backtrace/unwmemaccess.h"
+#include "../shared/backtrace/unwinder.h"
+#include "../shared/backtrace/unwmemaccess.h"
 
 // Debug monitor that dumps to the Programming port all status when
 // an exception or WDT timeout happens - And then resets the board

Marlin/src/HAL/shared/backtrace/backtrace.cpp

@@ -27,7 +27,7 @@
 #include "unwinder.h"
 #include "unwmemaccess.h"
 
-#include "../../core/serial.h"
+#include "../../../core/serial.h"
 #include <stdarg.h>
 
 // Dump a backtrace entry

platformio.ini

@@ -24,7 +24,7 @@ boards_dir  = buildroot/share/PlatformIO/boards
 env_default = megaatmega2560
 
 [common]
-default_src_filter = +<src/*> -<src/config>
+default_src_filter = +<src/*> -<src/config> -<src/HAL> +<src/HAL/shared>
 build_flags = -fmax-errors=5
   -g
   -ggdb