Context

Currently the get_certificate command exposed in command_handlers has defined its own encoding for Certificate_repr.t. This is because:

Certificate_repr.encoding is Json_only and here we need binary encoding
This command will be used by Kernel SDK which needs the root_hash field to be 33 bytes long (first byte must be 0 then 32 bytes of data)

The 33 bytes long encoding for root_hash is not possible without Plugin resolution. Hence, in this MR you will find

New GET /v0/serialized_certificate which returns the correctly encoded in Binary certificate
New type serialized_certificate inside Certificate_repr.V0.Protocol_dependant module, to make obvious all these operations are linked to the protocol.
Encoding for the previously new type
helper function to correctly serialize such a serialized_certificate type.
Reworked wait_for_certificate function, which now calls new endpoint GET /serialized_certificate to return a correctly binary encoded certificate.

Manually testing the MR

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

Edited May 31, 2023 by Gauthier