scripts: move subfolder_list.py to scripts/build/subfolder_list.py

Move scripts needed by the build system and not designed to be run
individually or standalone into the build subfolder.

Signed-off-by: Anas Nashif <anas.nashif@intel.com>

CMakeLists.txt

@@ -614,7 +614,7 @@ endif()
 execute_process(
   COMMAND
   ${PYTHON_EXECUTABLE}
-  ${ZEPHYR_BASE}/scripts/subfolder_list.py
+  ${ZEPHYR_BASE}/scripts/build/subfolder_list.py
   --directory        ${ZEPHYR_BASE}/include      # Walk this directory
   --out-file         ${syscalls_subdirs_txt}     # Write file with discovered folder
   --trigger          ${syscalls_subdirs_trigger} # Trigger file that is used for json generation
@@ -647,7 +647,7 @@ else()
     ${syscalls_subdirs_trigger}
     COMMAND
     ${PYTHON_EXECUTABLE}
-    ${ZEPHYR_BASE}/scripts/subfolder_list.py
+    ${ZEPHYR_BASE}/scripts/build/subfolder_list.py
     --directory        ${ZEPHYR_BASE}/include      # Walk this directory
     --out-file         ${syscalls_subdirs_txt}     # Write file with discovered folder
     --trigger          ${syscalls_subdirs_trigger} # Trigger file that is used for json generation