Proto/Michelson: move some translator functions to the gas monad

Context

For many elaboration and unparsing functions, the context is only used to consume gas. Moving them to the gas monad is useful to make them easier to call outside of the protocol.

This MR covers the easiest cases.

Stacked on !9631 (merged).

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