Enable rust target builds as well as nativesdk-rust for the sdk. Merge
the builds of rust-tools components into the rust build, packaged separately
since this is a lot more efficient and saves rebuilding core rust multiple
times. The tools are not target specific so nativesdk-rust-tools suffices
and we can drop the cross canadian piece.
(From OE-Core rev: b9b0cd99cdc77e7a90e5fd5711e706ebe64c7b6b)
Signed-off-by: Richard Purdie <richard.purdie@linuxfoundation.org>