Support `[%of_file]` and string code injection in `[%michelson]`

Motivation and Context

We are discussing removing the preprocessor. One of the (ab)uses of the preprocessor was to include a .tz file in the middle of a Michelson embedding with a CREATE_CONTRACT:

    [%Michelson ( {| { 
            UNPAIR ;
            UNPAIR ;
            CREATE_CONTRACT 
#include "generic_fa2/compiled/fa2_nft.tz"  
               ;
            PAIR } |}
              : lambda_create_contract)]

Description

In this MR we add two things in order to prevent this hack:

• An injection [%of_file "foo.txt"] that pastes the contents of foo.txt as a verbatim string in that place.
• A helper for [%michelson] of the form codestr that allows to embed Michelson argument.

We could write an embedding like that above as:

[%michelson ({| { PUSH unit Unit ; PUSH mutez 300000000 ; NONE key_hash ; CREATE_CONTRACT (codestr $0) ; PAIR } |} [%of_file "./interpreter_tests/contract_under_test/compiled.tz"] : operation * address)]

Component

• compiler
• website
• webide
• vscode-plugin
• debugger

Types of changes

• Bug fix (non-breaking change which fixes an issue)
• New feature (non-breaking change which adds functionality)
• Breaking change (fix or feature that would cause existing functionality to not work as expected)
• Performance improvement (non-breaking change that improves performance)
• None (change with no changelog)

Changelog

Checklist:

• Changes follow the existing coding style (use dune @fmt to check).
• Tests for the changes have been added (for bug fixes / feature).
• Documentation has been updated.
• Changelog description has been added (if appropriate).
• Start titles under ## Changelog section with #### (if appropriate).
• There is no image or uploaded file in changelog
• Examples in changed behaviour have been added to the changelog (for breaking change / feature).