Documentation: Move cbfstool & ifdtool dirs under util\

Change-Id: If1b263345baf321cde75058f310c96d89a95d62d
Signed-off-by: Martin Roth <gaumless@gmail.com>
Reviewed-on: https://review.coreboot.org/c/coreboot/+/64577
Tested-by: build bot (Jenkins) <no-reply@coreboot.org>
Reviewed-by: Felix Singer <felixsinger@posteo.net>

Documentation/util/ifdtool/index.md

@@ -0,0 +1,6 @@
+# ifdtool
+
+Contents:
+
+* [Intel IFD Binary Extraction](binary_extraction.md)
+* [IFD Layout](layout.md)