[Rachana-Kodal]

What this PR does / why we need it:
Implements attach/detach NIC to the NetH VMs

Result:

[Rajat-0]

The feature itself is clearly aimed at a real gap, but the NETH attach/config path has a couple of blockers in the new network configuration logic.

zvmsdk/networkops.py: zdirect_network_configuration() calls self._create_invokeScript(network_file_path, clean_cmd, files_map, znetconfig=False), but the method defined in the same class only accepts (network_file_path, commands, files_map). That mismatch will raise a TypeError as soon as guest_configure_network_interface_ip() is used, so the attach flow cannot work end-to-end.
zvmsdk/networkops.py: in _create_neth_configuration_files(), cfg_str is reassigned inside the loop instead of being appended to a per-interface config, so if guest_networks contains more than one entry, only the last network’s configuration survives. Earlier entries are silently dropped, which makes multi-NIC or repeated attach config incorrect.

[Rajat-0]

Also check PEP8 failure

[Rachana-Kodal]

Issue 1 – Fix: This issue has been fixed in #970

Issue 2 – Fix: Replaced the loop with direct indexing (net = network[0]) because each function call handles a single network interface. This ensures the intended network configuration is processed without accidentally overwriting it with subsequent entries.