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/workflows/issues-auto-label.yml

@@ -0,0 +1,17 @@
+# If the author of the issues is not a contributor to the project, label
+# the issue with 'Z0-unconfirmed'
+
+name: Label New Issues
+on:
+  issues:
+    types: [opened]
+
+jobs:
+  label-new-issues:
+    runs-on: ubuntu-latest
+    steps:
+      - name: Label drafts
+        uses: andymckay/labeler@e6c4322d0397f3240f0e7e30a33b5c5df2d39e90 # 1.0.4
+        if: github.event.issue.author_association == 'NONE'
+        with:
+          add-labels: "I10-unconfirmed"