feat: add slog logging (#432)

* feat(op): user slog for logging

integrate with golang.org/x/exp/slog for logging.
provide a middleware for request scoped logging.

BREAKING CHANGES:

1. OpenIDProvider and sub-interfaces get a Logger()
method to return the configured logger;
2. AuthRequestError now takes the complete Authorizer,
instead of only the encoder. So that it may use its Logger() method.
3. RequestError now takes a Logger as argument.

* use zitadel/logging

* finish op and testing
without middleware for now

* minimum go version 1.19

* update go mod

* log value testing only on go 1.20 or later

* finish the RP and example

* ping logging release

pkg/client/rp/log.go

@@ -0,0 +1,17 @@
+package rp
+
+import (
+	"context"
+
+	"github.com/zitadel/logging"
+	"golang.org/x/exp/slog"
+)
+
+func logCtxWithRPData(ctx context.Context, rp RelyingParty, attrs ...any) context.Context {
+	logger, ok := rp.Logger(ctx)
+	if !ok {
+		return ctx
+	}
+	logger = logger.With(slog.Group("rp", attrs...))
+	return logging.ToContext(ctx, logger)
+}