add `CheckMetadataHash` signed extension (#202) #473

Job	Run time
Cancel Previous Runs	5s
Benchmarking build release for on (ubuntu-20.04)	21m 13s
Live build release for on (ubuntu-20.04)	20m 43s
Build Runtimes (integritee-node)	10m 18s
cargo-toml-fmt	9s
Set up Config	1s
license-check	31s
Rust check +nightly fmt --all (x86_64-unknown-linux-gnu)	24s
create_artifacts (shell, kusama)	2s
Draft Release	0s
Publish Runtimes	0s
	53m 26s

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