refactor: Centralize resource path management

Create a new `settings.py` file to define and manage global application paths.

Modify UI components (`split_view_widget.py`, `view_settings_dialog.py`) to use the centralized `ICONS_DIR` path constant instead of hardcoded relative paths for icons. This improves maintainability and makes the application independent of the working directory.

settings.py

@@ -0,0 +1,13 @@
+from pathlib import Path
+
+# Absolutna ścieżka do głównego katalogu projektu
+ROOT_DIR = Path(__file__).parent.resolve()
+
+# Ścieżka do katalogu UI
+UI_DIR = ROOT_DIR / "ui"
+
+# Ścieżka do katalogu z ikonami
+ICONS_DIR = UI_DIR / "icons"
+
+# Ścieżka do katalogu z mediami
+MEDIA_DIR = ROOT_DIR / "media"