Rust

Add zk-nullifier example and reorganize zk/ folder #145

Job	Run time
basic-operations/native/native-program-update	1m 20s
basic-operations/native/native-program-create	1m 18s
zk/zk-merkle-proof	1m 0s
zk/zk-id	53s
create-and-update	1m 28s
airdrop-implementations/simple-claim/program	5m 30s
counter/pinocchio	1m 29s
account-comparison	1m 22s
counter/native	1m 19s
zk/zk-nullifier	1m 8s
basic-operations/native/native-program-burn	1m 25s
basic-operations/native/native-program-reinit	1m 21s
basic-operations/native/native-program-close	1m 34s
	21m 7s

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