Rewrite sdjwt-verifier in vanilla cosmwasm

## Problem 
During the multitesting DSD-verifier with avida-sdjwt-verifier i found that it would be quite tricky to implement tests, as sdjwt-verifier is written using Sylvia framework and SPV we decided to write in vanilla cosmwasm.

## Decision
This issue requires rewriting sdjwt-verifier in vanilla cosmwasm, probably upgrading the version of cosmwasm-std too.