Make cloud provider caching TTL configurable

[zqingqing1]

What type of PR is this?

/kind feature

What this PR does / why we need it:
The PR will make cloud provider caching TTL configurable, instead of only using static default value.

Which issue(s) this PR fixes:

Fixes #

Special notes for your reviewer:

Does this PR introduce a user-facing change?:

azure cloud provider cache TTL is configurable, list of the azure cloud provider is as following:
- "availabilitySetNodesCacheTTLInSeconds"
- "vmssCacheTTLInSeconds"
- "vmssVirtualMachinesCacheTTLInSeconds"
- "vmCacheTTLInSeconds"
- "loadBalancerCacheTTLInSeconds"
- "nsgCacheTTLInSeconds"
- "routeTableCacheTTLInSeconds"

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

- [Usage]: 
add settings at cloud provider config file, eg:
                 "availabilitySetNodesCacheTTLInSeconds": 100,
		"vmssCacheTTLInSeconds": 100,
		"vmssVirtualMachinesCacheTTLInSeconds": 100,
		"vmCacheTTLInSeconds": 100,
		"loadBalancerCacheTTLInSeconds": 100,
		"nsgCacheTTLInSeconds": 100,
		"routeTableCacheTTLInSeconds": 100,

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[k8s-ci-robot]

Hi @zqingqing1. Thanks for your PR.

I'm waiting for a kubernetes 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.

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[zqingqing1]

/assign @andyzhangx Can you help to review the change?

[andyzhangx]

/ok-to-test
/sig cloud-provider
/area provider/azure
/priority important-soon

[andyzhangx]

/test pull-kubernetes-e2e-aks-engine-azure
/test pull-kubernetes-e2e-azure-disk
/test pull-kubernetes-e2e-azure-disk-vmss

[andyzhangx]

Errors from staticcheck:
vendor/k8s.io/legacy-cloud-providers/azure/azure.go:190:18: unknown JSON option "omityempty" (SA5008)

Please review the above warnings. You can test via:
  hack/verify-staticcheck.sh <failing package>
If the above warnings do not make sense, you can exempt the line or file. See:
  https://staticcheck.io/docs/#ignoring-problems

[feiskyer]

@zqingqing1 could you also include new option list in the release note part of PR description?

[feiskyer]

/lgtm
/approve

[k8s-ci-robot]

[APPROVALNOTIFIER] This PR is APPROVED

This pull-request has been approved by: feiskyer, zqingqing1

The full list of commands accepted by this bot can be found here.

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Needs approval from an approver in each of these files:

• staging/src/k8s.io/legacy-cloud-providers/azure/OWNERS [feiskyer]

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[andyzhangx]

/hold
hold a while, run the e2e test on the new changes:
/test pull-kubernetes-e2e-aks-engine-azure
/test pull-kubernetes-e2e-azure-disk
/test pull-kubernetes-e2e-azure-disk-vmss

[feiskyer]

job passed

/hold cancel