feat: calculate sd_hash automatically in present function

[lukasjhan]

see: https://www.ietf.org/archive/id/draft-ietf-oauth-selective-disclosure-jwt-07.html#section-5.3.1

sd_hash = Hasher("<Issuer-signed JWT>~<Disclosure 1>~<Disclosure 2>~...~<Disclosure N>~", <algorithm from the disclosed JWT>)

[lukasjhan]

To summarize, what is needed when verifying KB jwt is
Verification of sd_hash value,
Verification of nonce value if necessary,
and 3. Verification of kb jwt signature