Add documentation for production use

The only reference I can find to using this operator is the tutorial: https://developer.hashicorp.com/vault/docs/platform/k8s/vso

I'm not looking for a tutorial, but deployment documentation for connecting to the Hasicorp Vault Cloud. I do not want to use Minikube for testing, nor do I need a `learn-vault-secrets-operator` repo to learn operator.

Instead I am looking for documentation to use operator. What does this do:

```
vault write auth/demo-auth-mount/config \
kubernetes_host="https://$KUBERNETES_PORT_443_TCP_ADDR:443"
```

Is it persistent? Why from inside a container? Why `demo-auth-mount`? I am not looking for a demo.

```
vault kv put kvv2/webapp/config username="static-user" password="static-password"
```

I do not need to create secrets, I have secrets already.

```
In production you do not want default_ttl="1m" or max_ttl="1m" set. This is too short and a longer TTL should be used. It is only done this way in this tutorial for demonstration purposes.
```

☝️ Ok, but then where is the production deployment documentation?

In short, there is a big difference between 'tutorial' and 'documentation'. I am looking for documentation to be able to deploy operator and use it in production so logging this here as a feature request.

Start with the Vault Secrets Operator tutorial linked in the issue and compare its Minikube, demo-auth-mount, secret-creation, and TTL guidance with production use of Vault Cloud. Done means documenting deployment and connection to Vault Cloud, use of existing secrets, persistence, and production-appropriate configuration without relying on the tutorial repository.

Written by the indexing model from the issue text.