feat: allow setting default subnet for custom vpc

[cnvergence]

Pull Request

• Make sure you have followed Kube-OVN Code Style.

What type of this PR

Examples of user facing changes:

• Features
• Bug fixes
• Docs
• Tests

Which issue(s) this PR fixes

Fixes #4172

[cnvergence]

/retest

[zbb88888]

the crd yamls should be updated too

[cnvergence]

right, do you have maybe a make target or script to generate this?

[zbb88888]

right, do you have maybe a make target or script to generate this?

maybe later,

[cnvergence]

ptal @bobz965

[cnvergence]

PR updated @bobz965 PTAL at your convienience

[zbb88888]

@oilbeater could you please help review?

[oilbeater]

I think we do not need another annotation for namespace, add the ovn.kubernetes.io/logical_switch should be enough for further pod processing just as in the default VPC. What do you think? @cnvergence @bobz965

[zbb88888]

ovn.kubernetes.io/logical_switch

oh, I saw the code:
namespace already has the ovn.kubernetes.io/logical_switch

[cnvergence]

@oilbeater @bobz965 thanks for the review
Thinking out loud, it should work with ovn.kubernetes.io/logical_switch by just overwriting the logical switch slice during namespace processing, let's try this.

[zbb88888]

please add some doc about the vpc spec, and clarify the usage details between vpc spec default subnet and namespace annotation logical switch list.

[cnvergence]

Thanks @bobz965, I will add the docs PR asap

[cnvergence]

PTAL @oilbeater

[oilbeater]

@cnvergence Thanks for your contribution!