Draft: Proto/Michelson: move the atomic cases of parse_data to the gas monad

Context

Stacked on !10227 (merged).

This is a continuation of !10071 (merged), and a preparation of !10200 and !10182.

In this MR, the atomic cases of the parse_data function are made context-free and moved to the gas monad. Thus allowing them to be called without context, in particular from outside of the protocol. This is useful in particular to elaborate addresses in the client (see !9946 (comment 1562948685)).

Manually testing the MR

Checklist

• Document the interface of any function added or modified (see the coding guidelines)
• Document any change to the user interface, including configuration parameters (see node configuration)
• Provide automatic testing (see the testing guide).
• For new features and bug fixes, add an item in the appropriate changelog (docs/protocols/alpha.rst for the protocol and the environment, CHANGES.rst at the root of the repository for everything else).
• Select suitable reviewers using the Reviewers field below.
• Select as Assignee the next person who should take action on that MR