🛠️ [TASK] : Update vote tx v2 to make it compatible with catalyst signed doc format

[Mr-Leshiy]

Summary

Need to rethink and update the current design for the vote tx v2 to be compatible or inherited from the Catalyst signed doc format.

Description

Following new design specs of the "Catalyst signed document` https://github.com/input-output-hk/catalyst-libs/tree/main/rust/signed_doc update the current structure of the vote tx v2 to be reused the same format of the signed document.