tools: add skeleton of kmod tool

If using libtool 2.4.2, running the script generated by libtool will not
work because libtool changes argv[0] to lt-progname.

To test this is necessary to either fix the installed
build-aux/ltmain.sh file or run the binary directly like in:

$ export LD_LIBRARY_PATH=$PWD/libkmod/.libs/
$ ./tools/.libs/kmod help
4 files changed