Optimized tolerations code in vpc-nat-gw

[ShaPoHun]

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  Optimized tolerations code in vpc-nat-gw

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• In the VpcNatSpec struct in types.go, the TolerationSeconds field should be of type int64 instead of integer.
• In the genNatGwStatefulSet function in vpc_nat_gateway.go, the tolerations variable can be removed and replaced with gw.Spec.Tolerations.
• In the VpcNatSpec struct in types.go, the VpcNatToleration struct can be removed since it is no longer used.
• In the install.sh and crd.yaml files, the toleration.effect field should be of type corev1.TaintEffect instead of string.
• In the install.sh and crd.yaml files, the toleration.operator field should be of type corev1.TolerationOperator instead of string.