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

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[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

changes made

[istio-testing]

In response to a cherrypick label: #15459 failed to apply on top of branch "release-1.24":

Applying: Add helm installation steps for multi-primary
Applying: Update clusterid
Applying: Update config steps
Applying: Edit steps
Applying: Update multi-primary steps
Applying: Update files and docs
Applying: Add primary-remote steps
Applying: Edit spacing
Applying: Remove var
Applying: Fix cluster name
Applying: Update snips
Applying: Update docs
Applying: Update commands
Applying: Update docs
Applying: Update note
Applying: Resolve comments and UTs
Applying: Add quotes
Applying: Run make gen
Applying: Add more quotes
Applying: Fix lints
Applying: fix lint and spelling
Applying: Update tests
Applying: Add new tests for helm
Applying: Fix test
Applying: Update go.mod
Applying: Update installation scripts
Applying: Update helm repo setup scripts
Applying: Update cleanup steps
Applying: Update script and lint
Applying: update cleanup step
Applying: Update cleanup steps
Applying: Update cleanup steps
Applying: Fix cleanup script
Applying: Fix installation steps
Applying: Update scripts
Applying: Update istio-system ns creation steps
Applying: Fix CRD cleanup
Using index info to reconstruct a base tree...
M	go.mod
Falling back to patching base and 3-way merge...
Auto-merging go.mod
Applying: Update Helm CRD Cleanup
Using index info to reconstruct a base tree...
M	go.mod
Falling back to patching base and 3-way merge...
Auto-merging go.mod
Applying: Update cleanup
Applying: Remove additional var
Applying: Resolve comments
Using index info to reconstruct a base tree...
M	go.mod
Falling back to patching base and 3-way merge...
Auto-merging go.mod
Applying: fix go.mod
Using index info to reconstruct a base tree...
M	go.mod
Falling back to patching base and 3-way merge...
Auto-merging go.mod
Applying: Fix lint
Applying: update charts for remote profile
Applying: Update indentation
Applying: Update indentation
Applying: Fix lint
Applying: Fix numbering
Applying: Update installation steps
Applying: Add missing steps
Applying: Update cleanup steps
Applying: Fix indentation
Applying: Update indentation
Applying: Resolve comments
Applying: Resolve comments
Applying: update go.mod
Applying: remove cleanup
Applying: Update CRD cleanup
Applying: Update cleanup
Applying: Update cleanup
Using index info to reconstruct a base tree...
M	go.mod
Falling back to patching base and 3-way merge...
Auto-merging go.mod
CONFLICT (content): Merge conflict in go.mod
error: Failed to merge in the changes.
hint: Use 'git am --show-current-patch=diff' to see the failed patch
hint: When you have resolved this problem, run "git am --continue".
hint: If you prefer to skip this patch, run "git am --skip" instead.
hint: To restore the original branch and stop patching, run "git am --abort".
hint: Disable this message with "git config advice.mergeConflict false"
Patch failed at 0060 Update cleanup

[istio-testing]

In response to a cherrypick label: new issue created for failed cherrypick: #15982