Add document of "use network resources in different AAD Tenant and Subscription" feature.

[bowen5]

What type of PR is this?
/kind documentation

What this PR does / why we need it:
Add document of "use network resources in different AAD Tenant and Subscription" feature.
Which issue(s) this PR fixes:

None.

Special notes for your reviewer:
None.

Release note:

Add document of "use network resources in different AAD Tenant and Subscription" feature. 

[k8s-ci-robot]

Hi @bowen5. Thanks for your PR.

I'm waiting for a kubernetes-sigs member to verify that this patch is reasonable to test. If it is, they should reply with /ok-to-test on its own line. Until that is done, I will not automatically test new commits in this PR, but the usual testing commands by org members will still work. Regular contributors should join the org to skip this step.

Once the patch is verified, the new status will be reflected by the ok-to-test label.

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[k8s-ci-robot]

[APPROVALNOTIFIER] This PR is NOT APPROVED

This pull-request has been approved by: bowen5
To complete the pull request process, please assign khenidak
You can assign the PR to them by writing /assign @khenidak in a comment when ready.

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[andyzhangx]

/hold
until kubernetes/kubernetes#88384 is merged

[feiskyer]

/ok-to-test
/hold cancel