Keep RG and Subs components from VNet when generating a subnet resourceId

[TheRSP]

This PR closes #

The changes in this PR are as follows:

• Support creating VMs connected to Subnets in different resource groups

I have read the contributing guidelines and have completed the following:

• [x] Tested my code end-to-end against a live Azure subscription.
• [ ] Updated the documentation in the docs folder for the affected changes.
• [x] Written unit tests against the modified code that I have made.
• [x] Updated the release notes with a new entry for this PR.
• [x] Checked the coding standards outlined in the contributions guide and ensured my code adheres to them.

If I haven't completed any of the tasks above, I include the reasons why here:

• Bug fix, no change to documented functionality.

• Below is a minimal example configuration that includes the new features, which can be used to deploy to Azure:

let myVnet = Arm.Network.virtualNetworks.resourceId("myvnet", groupName="other-group")
vm {
    name "myvm"
    username "azureuser"
    link_to_unmanaged_vnet myVnet
    subnet_name "default"
}

[ninjarobot]

Looks good, thanks again @TheRSP. Please resolve the merge conflict and I'll merge the PR.

[ninjarobot]

@TheRSP can you please resolve merge conflicts so this can be merged? Thank you!

[TheRSP]

Sorry for the delay. Merge should be fixed now.

[ninjarobot]

Thanks for your contribution! This is now released in 1.7.9 and available on nuget.