Add devops/misc/check-repo-cycles.jq to analyse repo JSON

devops/misc/check-repo-cycles.jq

+.state |
+map_values(
+  map_values(
+    . as $m |
+    map_values(
+      select(                        # We keep only records with errors
+        .root and                    # We need .root
+        (
+          $m[.root].root != null or  # A root should have no root itself
+          .parent != .root and       # We need .parent different .root
+          $m[.parent].root != .root  # The parent's root should the same root.
+        )
+      )
+    ) | select(length > 0)           # we keep only records with errors
+  ) | select(length > 0)             # we keep only records with errors
+)
\ No newline at end of file