Rust

Add zk-nullifier example and reorganize zk/ folder #135

Job	Run time
zk/zk-id	1m 11s
counter/native	1m 20s
zk/zk-nullifier	1m 10s
counter/pinocchio	1m 23s
basic-operations/native/native-program-burn	1m 21s
create-and-update	1m 21s
account-comparison	1m 11s
basic-operations/native/native-program-create	1m 22s
basic-operations/native/native-program-update	1m 22s
airdrop-implementations/simple-claim/program	1m 23s
basic-operations/native/native-program-reinit	1m 15s
basic-operations/native/native-program-close	1m 20s
	15m 39s

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