[#828] Support transaction rollup jakarta changes

Description

Add support for txr1 and tz4 addresses.

Problem: Jakarta introduced new Michelson type, tx_rollup_l2_address, used with the new key hash address types, prefixed with tz4.

Solution: Implement support for this in Morley.

NB: Because tz4 hashes are handled more or less as other key hashes, but can't be used directly neither as a 'KeyAddress', nor as 'KeyHash' (verified on the node), to maximize code reuse, a new type KeyHash' is introduced, which is a GADT parametrized by the key "level". KeyHash is then declared as a synonym for KeyHash' 'KeyHashKindRegular.

Problem: Jakarta introduced a new address type for transaction rollups. We need to support it in Morley.

Solution: Add typechecking support. Emulator support is left for a separate issue.

Again, to maximize code reuse, txr1 addresses reuse some of KeyHash code via another GADT datakind.

Related issue(s)

Resolves #828 (closed)

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