Add script to generate ebuilds from metadata

`cargo metadata` gives us a list of required packages, their versions
and their dependencies. We can use this to generate the ebuilds needed
to support the current Cargo.lock entries.

BUG=b:176846220
TEST=Generated all ebuilds for systembt. See crrev/c/2770279

Change-Id: I6bf9863dc7805a1dc8c83b8b3ebd28b8abfc37aa
Reviewed-on: https://chromium-review.googlesource.com/c/chromiumos/platform/dev-util/+/2766249
Reviewed-by: Allen Webb <allenwebb@google.com>
Commit-Queue: Abhishek Pandit-Subedi <abhishekpandit@chromium.org>
Tested-by: Abhishek Pandit-Subedi <abhishekpandit@chromium.org>
1 file changed