[#440] Disallow transferring ꜩ from a contract

Description

Problem: tezos-client prohibits transferring ꜩ from an originated contract (except using TRANSFER_TOKENS) while morley unconditionally allows such transactions.

Solution: Catch the previously uncaught tezos errors in morley-client and check in executeTransfer whether we're attempting to transfer tokens from an originated contract and it's not from TRANSFER_TOKENS (i.e. it's a global operation). Throw a newly created EETransactionFromContract error if that's the case.

Related issue(s)

Resolves #440 (closed)

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