[#594] Add configurable `Mutez` hedgehog generator

Description

Problem: At the moment, Cleveland offers a Mutez generator that uses the type's full range. However, in tests, you usually want the generated values to be constrained to a certain range.

Solution: add a hedgehog generator for Mutez whose range can be configured by the user. In order to be able to construct a mutez range, we also have to have an instance of Integral for Mutez in scope, so we added that instance as well.

Related issue(s)

Resolves #594 (closed)

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