Add backport function to release tools (#19568)

* Add backport function

* delete backport action

.github/workflows/backport.yml

@@ -1,61 +0,0 @@
-name: Backport PR to branch
-on:
-  issue_comment:
-    types: [created]
-
-permissions:
-  contents: write
-  issues: write
-  pull-requests: write
-
-jobs:
-  backport:
-    if: github.event.issue.pull_request != '' && contains(github.event.comment.body, '/backport to')
-    runs-on: ubuntu-20.04
-    steps:
-    - name: Extract backport target branch
-      uses: actions/github-script@v6
-      id: target-branch-extractor
-      with:
-        result-encoding: string
-        script: |
-          if (context.eventName !== "issue_comment") throw "Error: This action only works on issue_comment events.";
-
-          // extract the target branch name from the trigger phrase containing these characters: a-z, A-Z, digits, forward slash, dot, hyphen, underscore
-          const regex = /^\/backport to ([a-zA-Z\d\/\.\-\_]+)/;
-          target_branch = regex.exec(context.payload.comment.body);
-          if (target_branch == null) throw "Error: No backport branch found in the trigger phrase.";
-
-          return target_branch[1];
-    - name: Post backport started comment to pull request
-      uses: actions/github-script@v6
-      with:
-        script: |
-          const backport_start_body = `Started backporting to ${{ steps.target-branch-extractor.outputs.result }}: https://github.com/${context.repo.owner}/${context.repo.repo}/actions/runs/${process.env.GITHUB_RUN_ID}`;
-          await github.issues.createComment({
-            issue_number: context.issue.number,
-            owner: context.repo.owner,
-            repo: context.repo.repo,
-            body: backport_start_body
-          });
-    - name: Checkout repo
-      uses: actions/checkout@v3
-      with:
-        fetch-depth: 0
-    - name: Run backport
-      uses: ./tools/actions/backport
-      with:
-        target_branch: ${{ steps.target-branch-extractor.outputs.result }}
-        auth_token: ${{ secrets.GITHUB_TOKEN }}
-        pr_description_template: |
-          Backport of #%source_pr_number% to %target_branch%
-
-          /cc %cc_users%
-
-          ## Customer Impact
-
-          ## Testing
-
-          - [ ] For any change that affects the release process, please work with a maintainer to come up with a plan to test this.
-
-          ## Risk