add COIP support for ALB on outpost

[M00nF1sh]

add COIP support for ALB on outpost

This PR supports to specify the ID of the customer-owned address pool via annotation alb.ingress.kubernetes.io/customer-owned-ipv4-pool.

Note: coIPv4 pool for ALB should be immutable.

1. currently we don't have webhooks to enforce the immutability).
2. we didn't take the approach of recreate ALB if the coIPv4 pool changes, which is left as improvement for future versions. (depends on whether ALB exposes the API to modify coIP pool)

Test done

1. normal ALB continue to work without been impacted.
2. with coIPPool on normal subnet, got error "You must use a customer owned IPv4 pool with an Application Load Balancer on an Outpost"
3. with coIPPool on outpost subnet:

LoadBalancers:
- AvailabilityZones:
  - LoadBalancerAddresses: []
    OutpostId: op-<redacted>
    SubnetId: subnet-<redacted>
    ZoneName: us-west-2a
  CanonicalHostedZoneId: <redacted>
  CreatedTime: '2020-11-24T22:48:08.690000+00:00'
  CustomerOwnedIpv4Pool: ipv4pool-coip-<redacted>
  DNSName: k8s-echoserv-echoserv-<redacted>.us-west-2.elb.amazonaws.com
  IpAddressType: ipv4
  LoadBalancerArn: <redacted>
  LoadBalancerName: k8s-echoserv-echoserv-<redacted>
  Scheme: internet-facing
  SecurityGroups:
  - sg-<redacted>
  State:
    Code: active
  Type: application
  VpcId: vpc-<redacted>

[codecov-io]

Codecov Report

Merging #1685 (a11a989) into main (9e7d172) will increase coverage by 0.14%.
The diff coverage is 83.33%.

@@            Coverage Diff             @@
##             main    #1685      +/-   ##
==========================================
+ Coverage   46.19%   46.34%   +0.14%     
==========================================
  Files         110      110              
  Lines        5933     5957      +24     
==========================================
+ Hits         2741     2761      +20     
- Misses       2927     2930       +3     
- Partials      265      266       +1     

Impacted Files	Coverage Δ
pkg/model/elbv2/load_balancer.go	0.00% <ø> (ø)
pkg/deploy/elbv2/load_balancer_manager.go	20.24% <66.66%> (+1.77%)	⬆️
pkg/ingress/model_build_load_balancer.go	45.72% <88.88%> (+4.29%)	⬆️

---

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[fawadkhaliq]

How will be this surfaced to the user in the current approach if they still end up changing it?

[M00nF1sh]

added a check for drifted settings.
Now customer will saw errors in controller log and Ingress events if they changed it.

[k8s-ci-robot]

[APPROVALNOTIFIER] This PR is NOT APPROVED

This pull-request has been approved by: fawadkhaliq, M00nF1sh
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