feat: Add rebrand CI/CD workflows to main branch

- Add 72 rebrand workflow files (polkadot→pezkuwi, substrate→bizinikiwi, cumulus→pezcumulus)
- Add GitHub actions, issue templates, and configs
- Removed unnecessary workflows (fork-sync, gitspiegel, upstream-tracker, sync-templates, backport)
- Renamed zombienet test files to match new naming convention

.github/actions/set-up-gh/action.yml

@@ -0,0 +1,28 @@
+name: "install gh"
+description: "Install the gh cli in a debian based distro and switches to the PR branch."
+inputs:
+  pr-number:
+    description: "Number of the PR"
+    required: true
+  GH_TOKEN:
+    description: "GitHub token"
+    required: true
+outputs:
+  branch:
+    description: "Branch name for the PR"
+    value: ${{ steps.branch.outputs.branch }}
+runs:
+  using: "composite"
+  steps:
+    - name: Set up git
+      shell: bash
+      # Here it would get the script from previous step
+      run: git config --global --add safe.directory '*'
+    - run: gh pr checkout ${{ inputs.pr-number }}
+      shell: bash
+      env:
+        GITHUB_TOKEN: ${{ inputs.GH_TOKEN }}
+    - name: Export branch name
+      shell: bash
+      run: echo "branch=$(git rev-parse --abbrev-ref HEAD)" >> "$GITHUB_OUTPUT"
+      id: branch