Misc: add a small tool to graph manifest includes

This is a simple script that display a tree of manifest includes.
I wrote it as a quick tool to get an idea of how manifest were
structured.

Requires the anytree lib.
Simply pass the manifest you want to start from as an argument.

Sample output on RHCOS:
```
(L)manifest.yaml
└── (L)manifest-rhel-coreos-9.yaml
    └── manifest-rhel-9.2.yaml
        ├── common.yaml
        │   ├── fedora-coreos-config/manifests/system-configuration.yaml
        │   ├── fedora-coreos-config/manifests/ignition-and-ostree.yaml
        │   │   └── fedora-coreos-config/manifests/bootable-rpm-ostree.yaml
        │   ├── fedora-coreos-config/manifests/file-transfer.yaml
        │   ├── fedora-coreos-config/manifests/networking-tools.yaml
        │   ├── fedora-coreos-config/manifests/user-experience.yaml
        │   ├── fedora-coreos-config/manifests/shared-workarounds.yaml
        │   └── packages-rhcos.yaml
        └── packages-openshift.yaml
```

Author: jbtrystram

src/manifest_graph

@@ -0,0 +1,60 @@
+#!/usr/bin/python3 -u
+
+'''
+    Create a tree chart with all the manifest includes
+    symlinks are displayed with a (L) prefix
+'''
+
+import sys
+import yaml
+import os
+from anytree import Node, RenderTree
+
+def collect_included_files(filename, parent):
+    node = None
+
+    if os.path.islink(filename):
+      node = Node("(L)"+filename, parent=parent)
+      dest = os.readlink(filename)
+      collect_included_files(dest, parent=node)
+      return node
+    else:
+      node = Node(filename, parent=parent)
+
+    with open(filename, 'r') as file:
+        try:
+            data = yaml.safe_load(file)
+            if data is None:
+                return
+            include_paths = data.get('include')
+            if include_paths:
+                if not isinstance(include_paths, list):
+                    include_paths = [include_paths]
+
+                for include_path in include_paths:
+                    if not os.path.isabs(include_path):
+                        include_path = os.path.join(os.path.dirname(filename), include_path)
+                    if os.path.exists(include_path):
+                        collect_included_files(include_path, parent=node)
+            return node
+        except yaml.YAMLError as e:
+            print(f"Error parsing YAML file '{filename}': {e}")
+            sys.exit(1)
+        except Exception as e:
+            print(f"Error: {e}")
+            sys.exit(1)
+
+if __name__ == "__main__":
+    if len(sys.argv) != 2:
+        print("Usage: python manifest_graph <yaml_file>")
+        sys.exit(1)
+
+    yaml_file = sys.argv[1]
+    if not os.path.exists(yaml_file):
+        print(f"Error: File '{yaml_file}' not found.")
+        sys.exit(1)
+
+    root = collect_included_files(yaml_file, None)
+
+    for pre, _, node in RenderTree(root):
+        print("%s%s" % (pre, node.name))