[RFE] Setup ephemeral networking to report provisioning complete

## Current situation

Currently azure-init relies on the VM's network to pull provisioning metadata from IMDS and to report provisioning complete to Azure platform

## Impact

azure-init is vulnerable to guest network issues that could prevent it from getting provisioning metadata and reporting provisioning complete. The most common scenario is the default route being setup over non-primary interface, which will block traffic to IMDS/wireserver. There will also be other issues such as handling the VF (Virtual Function) network interface for VMs with accelerated networking enabled.

## Ideal future situation

azure-init should setup an ephemeral DHCP lease over the correct primary nic to pull information from IMDS and also uses the same lease to report provisioning complete. The lease should be released once done.

The issue names no files, entry points, or tests. Start by tracing azure-init's existing IMDS metadata and provisioning-completion network paths, then inspect how the primary NIC and accelerated-networking virtual function are handled. Done means provisioning can use an ephemeral DHCP lease on the correct NIC and release it afterward.

Written by the indexing model from the issue text.