[#75] UStore reader

Description

Problem: we need some simple way to read upgradeable contracts storage content.

Solution: add a tool which allows reading fields, submap values and has a special case for entrypoits.

Tested, example of query: stack exec morley-ustore-reader -- -A babylon.testnet.tezos.serokell.team -P 8732 -c KT18m7BfQWCJFWntHPJBJghM49x94gYNeGwE print-map-value -f invs --key '"r1"' --key-type string --value-type '(set address, address, option string, address, map nat (nat, option timestamp, option bytes))'

Cases tested manually:

• contract has no big_map
• value under such coordinates is not present in UStore
• all three cli commands work well in good scenarios

Related issue(s)

Resolves #75 (closed)

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