sm: Support generation of card-based ed25519 CSR.
* sm/call-agent.c (gpgsm_scd_pksign): Allow SHA512. Create proper S-expression for EdDSA signature. * sm/certreqgen.c (create_request): Force use of SHA512 when using a ed25519 key. * sm/misc.c (transform_sigval): Insert OID for ed25519.
- GnuPG-bug-id: T4013
- Signed-off-by: Damien Goutte-Gattat <dgouttegattat@incenp.org>