feat: http provider signing key addition (#10641)

# Which Problems Are Solved

HTTP Request to HTTP providers for Email or SMS are not signed.

# How the Problems Are Solved

Add a Signing Key to the HTTP Provider resources, which is then used to
generate a header to sign the payload.

# Additional Changes

Additional tests for query side of the SMTP provider.

# Additional Context

Closes #10067

---------

Co-authored-by: Marco A. <marco@zitadel.com>
(cherry picked from commit 8909b9a2a6)

cmd/setup/62.go

@@ -0,0 +1,27 @@
+package setup
+
+import (
+	"context"
+	_ "embed"
+
+	"github.com/zitadel/zitadel/internal/database"
+	"github.com/zitadel/zitadel/internal/eventstore"
+)
+
+var (
+	//go:embed 62.sql
+	addHTTPProviderSigningKey string
+)
+
+type HTTPProviderAddSigningKey struct {
+	dbClient *database.DB
+}
+
+func (mig *HTTPProviderAddSigningKey) Execute(ctx context.Context, _ eventstore.Event) error {
+	_, err := mig.dbClient.ExecContext(ctx, addHTTPProviderSigningKey)
+	return err
+}
+
+func (mig *HTTPProviderAddSigningKey) String() string {
+	return "62_http_provider_add_signing_key"
+}