1. fix variable shadowing for deferred function;
2. fix deep copy.

As we no longer use ovn ipam options, no need to reserve them

Changes and new features:
1. Introduce new CRD `ProviderNetwork` for underlay/vlan networking management;
2. Specify provider inetrface on nodes in provider network;
4. Exclude nodes in provider network;
5. Link local IPv6 address and route will NOT be transferred to OVS bridge;
6. Builtin hybrid network support - create/update/delete underlay/vlan networks dynamically;
7. Set MTU of Pod interface to provider interface's MTU on each node;
8. Add new fields in CRD `Vlan`.

Gateway node(s) forward egress traffic to external gateway based on
policy routing. Support both distributed and centralized gateway modes.
New properties are available in subnet spec: externalGateway,
policyRoutingPriority & policyRoutingTableID.

Signed-off-by: Wan Junjie <wanjunjie@bytedance.com>