Proto/Michelson: move internal operations

Context

This is the second part to answer issue #2035 (closed).

It moves internal operations from Operation_repr to Script_typed_ir and restricts them to actual internal operations that can be returned by the interpreter: transactions, originations and delegations.

Manually testing the MR

Continuous integration.

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). Existing tests cover the modifications.
• 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). No new feature or bug fix.
• Select suitable reviewers using the Reviewers field below.
• Select as Assignee the next person who should take action on that MR