Use new PCN format for settings config file

src/backend/pcn/globals_dict.py

@@ -0,0 +1,37 @@
+from collections import UserDict
+from typing import TYPE_CHECKING, Any, Dict, Iterator
+
+if TYPE_CHECKING:
+    from .section import Section
+
+PCN_GLOBALS: Dict[str, Any] = {}
+
+
+class GlobalsDict(UserDict):
+    def __init__(self, section: "Section") -> None:
+        super().__init__()
+        self.section = section
+
+    @property
+    def full_dict(self) -> Dict[str, Any]:
+        return {
+            **PCN_GLOBALS,
+            **(self.section.root if self.section.root else {}),
+            **(self.section.root.globals if self.section.root else {}),
+            "self": self.section,
+            "parent": self.section.parent,
+            "root": self.section.parent,
+            **self.data,
+        }
+
+    def __getitem__(self, key: str) -> Any:
+        return self.full_dict[key]
+
+    def __iter__(self) -> Iterator[str]:
+        return iter(self.full_dict)
+
+    def __len__(self) -> int:
+        return len(self.full_dict)
+
+    def __repr__(self) -> str:
+        return repr(self.full_dict)