Provide a FlowFuse Cloud hosted cache for safe NPM packages

### Description

As an IT / security conscience organisation, it'd be a challenge to control what's installed when NPM packages from npmjs.org are installed. For that FlowFuse allows customers to limit the packages that can be installed by
1. Blocking all packages (Firewall) and use pre-installed packages locally for edge devices
2. Allow Certified Nodes (self-hosted) with a Verdaccio cache, disallow others with a Firewall
3. Encourage Certified Nodes (FF Cloud) but still allow any packages to be installed through the Settings UI?

For FlowFuse Cloud customers on the Enterprise Tier it would be great if the firewall could allow just `packages.flowfuse.com` (for example) to update their Node-RED instances on devices, the device agents, and packages.

### Which customers would this be available to

Enterprise Tier Only (EE)