Replace legacy template with index template

[cliu123]

Description

This change replaces the legacy template with the new index template.
This PR depends on opensearch-project/security#2503, so the opensearch-project/security#2503 needs to be merged first.

Category

[Enhancement, New feature, Bug fix, Test fix, Refactoring, Maintenance, Documentation] Enhancement

Why these changes are required?

The new index template is the replacement of the legacy template.

Issues Resolved

#1222

Testing

UT & IT & Manual Testing

Check List

• Commits are signed per the DCO using --signoff

By submitting this pull request, I confirm that my contribution is made under the terms of the Apache 2.0 license.
For more information on following Developer Certificate of Origin and signing off your commits, please check here.

[codecov-commenter]

Codecov Report

Merging #1359 (23d4fc3) into main (293aed8) will not change coverage.
The diff coverage is n/a.

📣 This organization is not using Codecov’s GitHub App Integration. We recommend you install it so Codecov can continue to function properly for your repositories. Learn more

@@           Coverage Diff           @@
##             main    #1359   +/-   ##
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  Coverage   71.78%   71.78%           
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  Files          88       88           
  Lines        2027     2027           
  Branches      269      269           
=======================================
  Hits         1455     1455           
  Misses        509      509           
  Partials       63       63           

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[opensearch-trigger-bot]

The backport to opendistro-1.13 failed:

The process '/usr/bin/git' failed with exit code 1

To backport manually, run these commands in your terminal:

# Fetch latest updates from GitHub
git fetch
# Create a new working tree
git worktree add .worktrees/backport-opendistro-1.13 opendistro-1.13
# Navigate to the new working tree
cd .worktrees/backport-opendistro-1.13
# Create a new branch
git switch --create backport/backport-1359-to-opendistro-1.13
# Cherry-pick the merged commit of this pull request and resolve the conflicts
git cherry-pick -x --mainline 1 b69a364ebb70e19dedb4dbf21b1764b47a49f250
# Push it to GitHub
git push --set-upstream origin backport/backport-1359-to-opendistro-1.13
# Go back to the original working tree
cd ../..
# Delete the working tree
git worktree remove .worktrees/backport-opendistro-1.13

Then, create a pull request where the base branch is opendistro-1.13 and the compare/head branch is backport/backport-1359-to-opendistro-1.13.

[opensearch-trigger-bot]

The backport to opendistro-1.11 failed:

The process '/usr/bin/git' failed with exit code 1

To backport manually, run these commands in your terminal:

# Fetch latest updates from GitHub
git fetch
# Create a new working tree
git worktree add .worktrees/backport-opendistro-1.11 opendistro-1.11
# Navigate to the new working tree
cd .worktrees/backport-opendistro-1.11
# Create a new branch
git switch --create backport/backport-1359-to-opendistro-1.11
# Cherry-pick the merged commit of this pull request and resolve the conflicts
git cherry-pick -x --mainline 1 b69a364ebb70e19dedb4dbf21b1764b47a49f250
# Push it to GitHub
git push --set-upstream origin backport/backport-1359-to-opendistro-1.11
# Go back to the original working tree
cd ../..
# Delete the working tree
git worktree remove .worktrees/backport-opendistro-1.11

Then, create a pull request where the base branch is opendistro-1.11 and the compare/head branch is backport/backport-1359-to-opendistro-1.11.

[opensearch-trigger-bot]

The backport to opendistro-1.12 failed:

The process '/usr/bin/git' failed with exit code 1

To backport manually, run these commands in your terminal:

# Fetch latest updates from GitHub
git fetch
# Create a new working tree
git worktree add .worktrees/backport-opendistro-1.12 opendistro-1.12
# Navigate to the new working tree
cd .worktrees/backport-opendistro-1.12
# Create a new branch
git switch --create backport/backport-1359-to-opendistro-1.12
# Cherry-pick the merged commit of this pull request and resolve the conflicts
git cherry-pick -x --mainline 1 b69a364ebb70e19dedb4dbf21b1764b47a49f250
# Push it to GitHub
git push --set-upstream origin backport/backport-1359-to-opendistro-1.12
# Go back to the original working tree
cd ../..
# Delete the working tree
git worktree remove .worktrees/backport-opendistro-1.12

Then, create a pull request where the base branch is opendistro-1.12 and the compare/head branch is backport/backport-1359-to-opendistro-1.12.