Update NOTES.txt to be vocal about production guidelines

[bootc]

There's a note in the README.md about production usage, but we should probably have a big visible warning in the NOTES.txt to call out various potential issues that might impact production usage.

Most notably:

• Using the built-in/bundled PostgreSQL chart
• Using the built-in/bundled Redis chart
• Not supplying an external Secret

We can also offer less shouty advice about:

• Not using persistent storage (e.g. using object storage instead)
• Not setting affinity if replicaCount > 1