use util.hostNameEnv instead KUBE_NODE_NAME

perf: add fastpath and tuning guide

fix node labels and provider network status

status.readyNodes when provider network is not initialized successfully
in a node

fix issues in underlay networking

When nic used is changed, addresses and routes on the OVS bridge should be returned before adding the new nic to the OVS bridge.

When nodes are added to a provider network's `spec.excludeNodes`:
1. The nodes should be removed from the provider network's `status.readyNodes`;
2. If the provider network is being used by subnets, patch ports should be removed first by setting `ovn-bridge-mappings`;
3. Node labels should be updated first.

add external vpc switch

update Go to version 1.16

update versions in docs and yamls

fix IPv6-related issues

fix: bad udp checksum when access nodeport

Similar to https://github.com/flannel-io/flannel/issues/1279, unmark output to bypaas kernel bug and enable checksum for better performance.

fix port-security, address parameters should be merged into one

docs: optimize description

ensure provider nic is up

fix uninstall.sh

fix gofmt lint

some optimizations

fix multi-nic.md

fix dual stack cluster created by kind

fix default bind socket of cni server

remove external egress gateway from additionalPrinterColumns