Feature request: panos.sh deploy hook - Deploy a certificate to multiple template stacks

Please add support to the panos.sh deploy hook to deploy a certificate to multiple template stacks.

Currently, it's only possible to define a single template stack in `PANOS_TEMPLATE_STACK`

Start in `panos.sh` and find where `PANOS_TEMPLATE_STACK` is read and used in the `deploy` hook. Follow that logic to the actual deployment call so you can see how a single stack value is passed today, then update it to iterate over multiple stack entries. Check for similar multi-value env-var parsing patterns in other scripts, and update any usage/help text to document the new format. Validate by running the deploy path with a multi-stack `PANOS_TEMPLATE_STACK` value and verifying each stack is processed.

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