async start() {
        if (this.mode !== 'network') {
            return;
        }
        const existingWebhook = await this.StripeWebhook.get();

        const webhook = await this.setupWebhook(existingWebhook.webhook_id, existingWebhook.secret);

        await this.StripeWebhook.save({
            webhook_id: webhook.id,
            secret: webhook.secret
        });

        this.webhookSecret = webhook.secret;
    }
Starts the Stripe Webhook Endpoint and saves the webhook ID and secret.

@returns {Promise<void>}