refactor: use struct types for claim related types

BREAKING change.
The following types are changed from interface to struct type:

- AccessTokenClaims
- IDTokenClaims
- IntrospectionResponse
- UserInfo and related types.

The following methods of OPStorage now take a pointer to a struct type,
instead of an interface:

- SetUserinfoFromScopes
- SetUserinfoFromToken
- SetIntrospectionFromToken

The following functions are now generic, so that type-safe extension
of Claims is now possible:

- op.VerifyIDTokenHint
- op.VerifyAccessToken
- rp.VerifyTokens
- rp.VerifyIDToken

pkg/op/session.go

@@ -59,7 +59,7 @@ func ValidateEndSessionRequest(ctx context.Context, req *oidc.EndSessionRequest,
 		RedirectURI: ender.DefaultLogoutRedirectURI(),
 	}
 	if req.IdTokenHint != "" {
-		claims, err := VerifyIDTokenHint(ctx, req.IdTokenHint, ender.IDTokenHintVerifier(ctx))
+		claims, err := VerifyIDTokenHint[*oidc.TokenClaims](ctx, req.IdTokenHint, ender.IDTokenHintVerifier(ctx))
 		if err != nil {
 			return nil, oidc.ErrInvalidRequest().WithDescription("id_token_hint invalid").WithParent(err)
 		}