Proto-env: remove (wrapped false)

Context

Remove the last use of (wrapped false) in the codebase and remove the feature from the manifest.

3 modules have been added to the "public" interface Tezos_protocol_environement.

module Memory_context = Memory_context
module Proxy_context = Proxy_context
module Proxy_delegate = Proxy_delegate

Modules only meant to be used for tests are now are now under a special module

module Internal_for_tests = struct
  module Environment_protocol_T_test = Environment_protocol_T_test
  module Environment_cache = Environment_cache
end 

This MR also

• moves individual library into separate directories
• remove the unused Dummy_context

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