Using Kustomize, we can define the configuration file separately from
the Kubernetes resources, and use `configMapGenerators` to generate the
ConfigMap for it. Additionally, this will make it possible to update
_ntfy_ using `updatebot`.
Now that the reverse proxy that handles requests from the Internet uses
TLS pass-through, the Ingress for _ntfy_ needs to recognize both the
internal and external name.
*ntfy* allows notifications to include arbitrary file attachments. For
images, it will even show them in the notification. In order to support
this, the server must be configured with a writable filesystem location
to cache the files.
Dustin