Document how API service pods can use config/secret reloaders to track cert rotation

[kd7lxl]

Konk uses certificate manager to sign relatively short lifespan certificates. After certificates are automatically rotated, the api service using them needs to begin using the new cert value. For cases where the service itself cannot do this itself, there is a common pattern in Kubernetes that uses a config reloader sidecar. This is a common use case and should be described in konk documentation.

[kd7lxl]

Since dynamic reload of certs is supported by the Kubernetes SDK, using another type of reloader is an edge case. We expect most users will use the SDK. Documenting how to not use the SDK is a low priority.