recipetool: create: add support for out-of-tree kernel modules

recipetool: create: add support for out-of-tree kernel modules

Detect kernel modules by looking for #include <linux/module.h>, and
handle the various styles of Makefile that appear to be used. I was able
to use this code to successfully build a number of external kernel
modules I found.

Implements [YOCTO #8982].

Signed-off-by: Paul Eggleton <paul.eggleton@linux.intel.com>
Signed-off-by: Ross Burton <ross.burton@intel.com>