Rust

Add zk-nullifier example and reorganize zk/ folder #143

Job	Run time
counter/native	1m 18s
zk/zk-nullifier	1m 9s
create-and-update	1m 18s
zk/zk-id	1m 18s
account-comparison	1m 19s
zk/zk-merkle-proof	1m 15s
counter/pinocchio	1m 19s
basic-operations/native/native-program-close	1m 18s
basic-operations/native/native-program-update	1s
basic-operations/native/native-program-burn	1m 18s
airdrop-implementations/simple-claim/program	1m 18s
basic-operations/native/native-program-create	1m 15s
basic-operations/native/native-program-reinit	1m 19s
	15m 25s

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