binman: Add a bintool implementation for futility

Add a Bintool for this, which is used to sign Chrome OS images and
build the Google Binary Block (GBB). It supports the features needed by
binman as well as fetching a binary from Google Drive. Building it from
source is possible but is left for another time, as it requires at least
one other library.

Signed-off-by: Simon Glass <sjg@chromium.org>
1 file changed