Add convenience method for cloning key value entry

[iamyulong]

Summary

Add a convenience method for cloning key value entry, similar to how we would normally do with HashMap entries.

[github-actions]

Docker tags
docker.io/radixdlt/private-scrypto-builder:5c1ce6afe2

[github-actions]

Benchmark for 5c1ce6a

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Test	Base	PR	%
costing::bench_prepare_wasm	66.2±0.36ms	66.0±0.12ms	-0.30%
costing::decode_sbor	10.9±0.02µs	11.0±0.03µs	+0.92%
costing::decode_sbor_bytes	29.6±0.05µs	29.5±0.02µs	-0.34%
costing::deserialize_wasm	1301.7±4.55µs	1306.6±2.89µs	+0.38%
costing::instantiate_flash_loan	4.0±0.66ms	4.0±0.71ms	0.00%
costing::instantiate_radiswap	5.8±0.07ms	5.8±0.08ms	0.00%
costing::spin_loop	23.3±0.46ms	22.3±0.16ms	-4.29%
costing::validate_sbor_payload	30.2±0.05µs	30.3±0.05µs	+0.33%
costing::validate_sbor_payload_bytes	249.2±2.41ns	264.0±0.75ns	+5.94%
costing::validate_secp256k1	76.7±0.05µs	76.7±0.04µs	0.00%
costing::validate_wasm	37.6±0.04ms	37.0±0.05ms	-1.60%
decimal::add/0	8.4±0.00ns	8.5±0.06ns	+1.19%
decimal::add/rust-native	9.8±0.00ns	9.8±0.00ns	0.00%
decimal::add/wasmer	112.1±0.22ns	116.5±0.05ns	+3.93%
decimal::add/wasmer-call-native	451.8±0.26ns	450.4±0.18ns	-0.31%
decimal::add/wasmi	658.9±0.65ns	745.7±6.73ns	+13.17%
decimal::add/wasmi-call-native	5.3±0.00µs	5.6±0.01µs	+5.66%
decimal::div/0	191.5±0.12ns	190.9±0.46ns	-0.31%
decimal::from_string/0	150.6±0.19ns	151.3±0.25ns	+0.46%
decimal::mul/0	142.4±0.10ns	142.1±0.17ns	-0.21%
decimal::mul/rust-native	138.3±0.16ns	139.7±0.11ns	+1.01%
decimal::mul/wasmer	1516.3±0.59ns	1479.4±1.46ns	-2.43%
decimal::mul/wasmer-call-native	582.7±0.70ns	585.6±0.57ns	+0.50%
decimal::mul/wasmi	41.9±0.06µs	41.5±0.07µs	-0.95%
decimal::mul/wasmi-call-native	5.4±0.00µs	5.4±0.01µs	0.00%
decimal::pow/0	648.2±0.65ns	654.8±1.07ns	+1.02%
decimal::pow/rust-native	636.3±0.30ns	637.0±0.88ns	+0.11%
decimal::pow/wasmer	6.6±0.01µs	6.6±0.01µs	0.00%
decimal::pow/wasmer-call-native	1023.8±0.74ns	1029.0±1.40ns	+0.51%
decimal::pow/wasmi	196.8±0.31µs	198.9±0.32µs	+1.07%
decimal::pow/wasmi-call-native	5.3±0.01µs	5.2±0.01µs	-1.89%
decimal::root/0	7.9±0.00µs	7.7±0.00µs	-2.53%
decimal::sub/0	8.5±0.01ns	8.5±0.01ns	0.00%
decimal::to_string/0	443.3±0.96ns	445.7±1.29ns	+0.54%
precise_decimal::add/0	9.4±0.04ns	9.3±0.13ns	-1.06%
precise_decimal::add/rust-native	11.6±0.00ns	11.6±0.00ns	0.00%
precise_decimal::add/wasmer	126.8±0.11ns	126.6±0.11ns	-0.16%
precise_decimal::add/wasmer-call-native	492.3±0.87ns	491.4±0.25ns	-0.18%
precise_decimal::add/wasmi	804.8±1.88ns	816.9±1.53ns	+1.50%
precise_decimal::add/wasmi-call-native	6.8±0.01µs	6.8±0.01µs	0.00%
precise_decimal::div/0	305.0±2.35ns	303.9±0.97ns	-0.36%
precise_decimal::from_string/0	196.9±0.10ns	196.4±0.14ns	-0.25%
precise_decimal::mul/0	353.7±2.04ns	355.0±1.72ns	+0.37%
precise_decimal::mul/rust-native	317.9±1.17ns	314.3±2.57ns	-1.13%
precise_decimal::mul/wasmer	3.4±0.00µs	3.4±0.00µs	0.00%
precise_decimal::mul/wasmer-call-native	816.6±0.81ns	822.2±1.44ns	+0.69%
precise_decimal::mul/wasmi	107.8±0.15µs	107.9±0.19µs	+0.09%
precise_decimal::mul/wasmi-call-native	7.1±0.02µs	7.2±0.03µs	+1.41%
precise_decimal::pow/0	1844.7±1.97ns	1845.0±2.57ns	+0.02%
precise_decimal::pow/rust-native	1476.9±6.92ns	1489.1±5.57ns	+0.83%
precise_decimal::pow/wasmer	16.1±0.01µs	16.1±0.01µs	0.00%
precise_decimal::pow/wasmer-call-native	2.1±0.00µs	2.1±0.00µs	0.00%
precise_decimal::pow/wasmi	518.1±0.76µs	524.6±2.28µs	+1.25%
precise_decimal::pow/wasmi-call-native	13.0±0.04µs	13.1±0.07µs	+0.77%
precise_decimal::root/0	55.3±0.02µs	56.6±0.18µs	+2.35%
precise_decimal::sub/0	9.5±0.00ns	9.5±0.01ns	0.00%
precise_decimal::to_string/0	729.4±1.45ns	732.3±2.60ns	+0.40%
schema::validate_payload	357.8±0.72µs	343.4±0.35µs	-4.02%
transaction::radiswap	5.5±0.02ms	5.5±0.02ms	0.00%
transaction::transfer	1850.7±7.29µs	1833.1±8.21µs	-0.95%
transaction_processing::prepare	2.2±0.00ms	2.2±0.00ms	0.00%
transaction_processing::prepare_and_decompile	6.2±0.01ms	6.2±0.02ms	0.00%
transaction_processing::prepare_and_decompile_and_recompile	27.1±2.39ms	24.9±1.58ms	-8.12%
transaction_validation::validate_manifest	42.3±0.03µs	42.3±0.21µs	0.00%
transaction_validation::verify_bls_2KB	1010.0±14.40µs	1084.5±53.89µs	+7.38%
transaction_validation::verify_bls_32B	1047.1±30.97µs	1070.9±18.99µs	+2.27%
transaction_validation::verify_ecdsa	74.5±0.04µs	74.6±0.07µs	+0.13%
transaction_validation::verify_ed25519	55.4±0.51µs	55.2±0.04µs	-0.36%