feat(elasticloadbalancingv2): denyAllIgwTraffic and clientRoutingPolicy for NLB (#29521)

### Issue # (if applicable)

Closes #29520.

### Reason for this change

NLB supports `ipv6.deny_all_igw_traffic` and
`dns_record.client_routing_policy` but these are not configurable from
AWS CDK.

### Description of changes

- add `zonalAffinity` props to `NetworkLoadBalancerProps`
- add `denyAllIgwTraffic` props to `BaseLoadBalancerProps`
  - `ipv6.deny_all_igw_traffic` is also supported by ALB

### Description of how you validated changes

I've added both unit and integ tests.

### Checklist
- [x] My code adheres to the [CONTRIBUTING
GUIDE](https://github.com/aws/aws-cdk/blob/main/CONTRIBUTING.md) and
[DESIGN
GUIDELINES](https://github.com/aws/aws-cdk/blob/main/docs/DESIGN_GUIDELINES.md)

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*By submitting this pull request, I confirm that my contribution is made
under the terms of the Apache-2.0 license*

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Co-authored-by: GZ <[email protected]>

Author: badmintoncryer