[GAIN-PoC] Authz request - nonce parameter is REQUIRED for SPID and CIE id

[peppelinux]

In The authz request the nonce parameter is required to prevent replay attacks using the implicit flow, SPID and CIE id doesnt support the implicit flow.

Using auth code flow the nonce is not required, following OIDC Core that defines it as OPTIONAL.

At the same time, SPID and CIE id are based on OIDC iGov, and this latter defines the nonce parameter in the Authz request as REQUIRED

https://openid.net/specs/openid-igov-openid-connect-1_0-03.html