scripts: move gen_strerror_table.py to scripts/build

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>

lib/libc/minimal/CMakeLists.txt

@@ -42,7 +42,7 @@ add_custom_command(
   OUTPUT ${STRERROR_TABLE_H}
   COMMAND
   ${PYTHON_EXECUTABLE}
-  ${ZEPHYR_BASE}/scripts/gen_strerror_table.py
+  ${ZEPHYR_BASE}/scripts/build/gen_strerror_table.py
   -i include/errno.h
   -o ${STRERROR_TABLE_H}
   DEPENDS include/errno.h

lib/libc/minimal/source/string/strerror.c

@@ -10,7 +10,7 @@
 #include <zephyr/sys/util.h>
 
 /*
- * See scripts/gen_strerror_table.py
+ * See scripts/build/gen_strerror_table.py
  *
  * #define sys_nerr N
  * const char *const sys_errlist[sys_nerr];