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/ISSUE_TEMPLATE/feature.yaml

@@ -0,0 +1,55 @@
+name: Feature Request
+description: Submit your requests and suggestions to improve!
+labels: [ I5-enhancement ]
+body:
+  - type: checkboxes
+    id: existing
+    attributes:
+      label: Is there an existing issue?
+      description: Please search to see if an issue already exists and leave a comment that you also experienced this issue or add your specifics that are related to an existing issue.
+      options:
+        - label: I have searched the existing issues
+          required: true
+  - type: checkboxes
+    id: stackexchange
+    attributes:
+      label: Experiencing problems? Have you tried our Stack Exchange first?
+      description: Please search <https://exchange.pezkuwichain.app> to see if an post already exists, and ask if not. Please do not file support issues here.
+      options:
+        - label: This is not a support question.
+          required: true
+  - type: textarea
+    id: motivation
+    attributes:
+      label: Motivation
+      description: Please give precedence as to what lead you to file this issue.
+      # placeholder: Describe ...
+    validations:
+      required: false
+  - type: textarea
+    id: request
+    attributes:
+      label: Request
+      description: Please describe what is needed.
+      # placeholder: Describe what you would like to see added or changed.
+    validations:
+      required: true
+  - type: textarea
+    id: solution
+    attributes:
+      label: Solution
+      description: If possible, please describe what a solution could be.
+      # placeholder: Describe what you would like to see added or changed.
+    validations:
+      required: false
+  - type: dropdown
+    id: help
+    attributes:
+      label: Are you willing to help with this request?
+      multiple: true
+      options:
+        - Yes!
+        - No.
+        - Maybe (please elaborate above)
+    validations:
+      required: true