Operating on a module collection

**Is your feature request related to a problem? Please describe.**
When using a module together with a for-expression there is sometimes the need to conveniently handle all similar outputs from a module. For instance, let's say I have a module that creates a number of virtual machines, and I have an output with that machine's IP address or hostname. In my `main.bicep` file I might want to collectively output all the output IP addresses/hostnames.

**Describe the solution you'd like**
Given I have a module for a virtual machine like this:

```bicep
// modules/vm.bicep
resource vm 'Microsoft.Compute/virtualMachines@2022-03-01' = {
// details skipped for brevity
}

resource publicIp 'Microsoft.Network/publicIPAddresses@2022-05-01' = {
// details skipped for brevity
}

output hostname string = publicIp.properties.dnsSettings.fqdn
```

In my `main.bicep` file I create a number of vm's with this module, then I would like to output an array of hostnames for all the vm's, collectively referring to them with `vms[*].outputs.hostname`:

```bicep
module vms 'modules/vm.bicep' = [for i in range(0,10): {
// details skipped for brevity
}]

output allHostnames array = vms[*].outputs.hostname
```

Start with the module example in modules/vm.bicep and the consuming expression in main.bicep, then trace how module collections and for-expressions are currently handled. Done means the shown vms[*].outputs.hostname form produces the collective hostname array for the module instances.

Written by the indexing model from the issue text.