Raw public keys support for JWT authentication

[maxtropets]

Closes #6601

Key points

• JsonWebKeyData created to avoid further changes in JsonWebKey, which is used for UVM endorsements parsing, as well as a base class for a plethora of key classes, which in turn are used in various key conversion APIs. Didn’t have enough courage to change that here.
• Crypto hierarchy issues ( Fix RSAPublicKey hierarchy and hidden virtual functions #6673 ) are not addressed here, but using RSA keys instead of misused EC keys has been fixed.
• Following the approach of JWT issuer validation #6175, the new key metadata table has been introduced to work with the new tables, previous metadata becomes “legacy” alongside old public_signing_key and public_signing_key_issuer tables. These are to be pruned in Cleanup old JWT tables in 5.0.1+ #6222, the ticket has been updated to mention the current change.
• nbf claim is no longer mandatory, as it's Entra-specific, details here.

[maxtropets]

Pending manual test, but ready for review

[PallabPaul]

Thank you for these changes! They look good to me overall. I made some comments which were mainly questions to get a better understanding of some parts of the code/logic that was implemented. Definitely want to dive deeper into the code outside of this PR as well to get a better understanding of the full flow but these changes look good as far as my knowledge of the jwt validation goes, thanks again!