Use Node TransportIP interface to send EgressIP gratuitous arp

[Jexf]

1. Use transportInterface as Egress external interface to send EgressIP gratuitous arp.

2. Remove unused field in Cluster struct.

Signed-off-by: Wu zhengdong zhengdong.wu@transwarp.io

[codecov-commenter]

Codecov Report

Merging #2845 (51c09e6) into main (e880406) will increase coverage by 20.71%.
The diff coverage is 0.00%.

@@             Coverage Diff             @@
##             main    #2845       +/-   ##
===========================================
+ Coverage   40.90%   61.61%   +20.71%     
===========================================
  Files         158      284      +126     
  Lines       19539    23469     +3930     
===========================================
+ Hits         7992    14460     +6468     
+ Misses      10798     7461     -3337     
- Partials      749     1548      +799     

Flag	Coverage Δ
kind-e2e-tests	49.22% <0.00%> (?)
unit-tests	40.88% <0.00%> (-0.02%)	⬇️

Flags with carried forward coverage won't be shown. Click here to find out more.

Impacted Files	Coverage Δ
pkg/agent/controller/egress/egress_controller.go	39.79% <0.00%> (ø)
.../controller/egress/ipassigner/ip_assigner_linux.go	0.00% <0.00%> (ø)
pkg/agent/memberlist/cluster.go	71.98% <ø> (-0.14%)	⬇️
pkg/apiserver/handlers/webhook/convert_crd.go	2.56% <0.00%> (ø)
pkg/apiserver/handlers/webhook/mutation_labels.go	24.71% <0.00%> (ø)
...et/versioned/typed/system/v1beta1/system_client.go	45.45% <0.00%> (ø)
pkg/apis/controlplane/v1beta2/conversion.go	60.00% <0.00%> (ø)
pkg/legacyapis/stats/register.go	81.81% <0.00%> (ø)
...et/versioned/typed/core/v1alpha2/externalentity.go	28.04% <0.00%> (ø)
...legacyclient/listers/core/v1alpha2/clustergroup.go	9.09% <0.00%> (ø)
... and 233 more

[jianjuns]

LGTM.

[tnqn]

Code LGTM. Two comments for commit message:

1. s/feild/field/
2. no need to append PR ID to commit title as Github will add one when squashing and merging, which will lead to 2 PR IDs.

[Jexf]

Code LGTM. Two comments for commit message:

1. s/feild/field/
2. no need to append PR ID to commit title as Github will add one when squashing and merging, which will lead to 2 PR IDs.

@tnqn Thanks for the review, updated.

[tnqn]

LGTM

[tnqn]

/test-all

[Jexf]

/test-ipv6-only
/test-ipv6-all