Add device name to ec ps and monitor

[gilesknap]

as per #227

[coretl]

Call it description and make it generic for all services

[gilesknap]

@coretl in fact we have called it:

labels:
  description: your description HERE
  another: future expansion of labels could go here

So that it can be expanded in future without changing the helm charts or schemas.

All the labels listed will just get added to the metadata of the statefulset and pod of the IOC (and possibly in future any other charts that decide to add this feature).

It will also be added as a label on the ArgoCD App, so that you can filter on these labels both in the ArgoCD GUI and the K8S dashboard.

[gilesknap]

@OCopping please can you drop a note in the README.md about how to get the pre-commit schema generation working locally. (Make it clear that this is required or CI will fail)

[gilesknap]

@OCopping yesterday we were passing the labels from the App down to the helm charts, but we forgot to actually add them to the App itself. That should be easy to work out - there is already the 'enabled' label as an example of where this would go.