Add helm installation steps for multi-cluster

[nshankar13]

Description

Adds Helm multi-cluster installation steps for all Istio multi-cluster control plane models and network topologies.

Preview link for quick reference: https://deploy-preview-15459--preliminary-istio.netlify.app/latest/docs/setup/install/multicluster/multi-primary/

Resolves: #14765

Tested against Istio 1.24.0 Helm charts.

Reviewers

• Ambient
• Docs
• Installation
• Networking
• Performance and Scalability
• Extensions and Telemetry
• Security
• Test and Release
• User Experience
• Developer Infrastructure
• Localization/Translation

[istio-policy-bot]

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Courtesy of your friendly welcome wagon.

[dhawton]

Since you're updating snips here, make sure they get added to the testing.

[nshankar13]

@dhawton any ideas on why the lint check is complaining about spelling here?

"Install Istio as primary in cluster1 using istioctl and the IstioOperator api"

[dhawton]

@dhawton any ideas on why the lint check is complaining about spelling here?

"Install Istio as primary in cluster1 using istioctl and the IstioOperator api"

Running locally (make lint) is easier to identify. It's because it's API not api.

[nshankar13]

/test doc.test.profile-default

[nshankar13]

/retest-required

[nshankar13]

/test doc.test.profile-default

[craigbox]

/retest-required

[craigbox]

/test doc.test.profile-default

multicluster log says

Error: INSTALLATION FAILED: Unable to continue with install: CustomResourceDefinition "wasmplugins.extensions.istio.io" in namespace "" exists and cannot be imported into the current release: invalid ownership metadata; annotation validation error: missing key "meta.helm.sh/release-name": must be set to "istio-base"; annotation validation error: missing key "meta.helm.sh/release-namespace": must be set to "istio-system"

[istio-testing]

@nshankar13: The following tests failed, say /retest to rerun all failed tests or /retest-required to rerun all mandatory failed tests:

Test name	Commit	Details	Required	Rerun command
doc.test.multicluster_istio.io	b06ee3e	link	true	/test doc.test.multicluster
doc.test.profile-default_istio.io	b06ee3e	link	true	/test doc.test.profile-default

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