🔥(back) remove footer endpoint

With the configuration file, the footer endpoint can be removed and will
not be used anymore by the front application.

src/backend/core/services/config_services.py

@@ -1,25 +0,0 @@
-"""Config services."""
-
-import logging
-
-import requests
-
-logger = logging.getLogger(__name__)
-
-
-def get_footer_json(footer_json_url: str) -> dict:
-    """
-    Fetches the footer JSON from the given URL."
-    """
-    try:
-        response = requests.get(
-            footer_json_url, timeout=5, headers={"User-Agent": "Docs-Application"}
-        )
-        response.raise_for_status()
-
-        footer_json = response.json()
-
-        return footer_json
-    except (requests.RequestException, ValueError) as e:
-        logger.error("Failed to fetch footer JSON: %s", e)
-        return {}