Track2 sdk: Add cache module in azclient

[MartinForReal]

What type of PR is this?

/kind feature

What this PR does / why we need it:

Track2 sdk: Add cache module in azclient

Which issue(s) this PR fixes:

Fixes #

Special notes for your reviewer:

Does this PR introduce a user-facing change?

NONE

Additional documentation e.g., KEPs (Kubernetes Enhancement Proposals), usage docs, etc.:

[mainred]

What's the difference between these cache from https://github.com/kubernetes-sigs/cloud-provider-azure/blob/master/pkg/cache/azure_cache.go?
And how are you going to use azclient/cache to replace pkg/cache/azure_cache?

[MartinForReal]

It is the same except that is is a module and it adopts golang generics.
It will be a dependency of generated repo implementation.

[andyzhangx]

pkg/cache/azure_cache.go?

@MartinForReal so will you remove the pkg/cache/azure_cache.go?

[MartinForReal]

yes. but we can keep it until it is not used.

[mainred]

Thanks for creating this PR. Since azclient is created as a separate module for more than just cloud-provider-azure, we can share the cache.
I will approve the PR but please confirm the following questions are not blockers to this PR.

My concerns:

1. why we reinvent deepcopy?
2. How are we going to protect the release of this module? we don't have e2e for this.
3. when do we plan to onboard this module to cloud-provider-azure? asking this because I am working on vmss-cache etag change, and there's conflicts.

[k8s-ci-robot]

[APPROVALNOTIFIER] This PR is APPROVED

This pull-request has been approved by: mainred, MartinForReal

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