[release-1.24] Add helm installation steps for multi-cluster

[istio-testing]

Manual cherrypick required.

#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

[craigbox]

@nshankar13 Niranjan, are you OK to handle this manually? It should hoepfully only involve picking everything except go.mod

[nshankar13]

@craigbox yes, can handle this

[craigbox]

Fixed by #16004.