Move configuration magic from `finalize_app` to the start of extension loading

While the approach with finalize_app worked well enough for most use cases, some extensions (especially cache-related ones) liked to initialize clients with the current config values baked in. Keeping track of those just to change their connection details would be unreasonable from a maintenance perspective.

Instead, we now set the values before any extension has the chance to cache any config values, thus eliminating this problem.

invenio_config_tuw/startup/__init__.py

@@ -14,7 +14,7 @@ initialized, and thus we can rely on them being already available.
 """
 
 
-from .config import finalize_config, patch_flask_create_url_adapter
+from .config import patch_flask_create_url_adapter
 from .misc import (
     customize_curation_request_type,
     override_search_drafts_options,
@@ -24,7 +24,6 @@ from .misc import (
 
 __all__ = (
     "customize_curation_request_type",
-    "finalize_config",
     "override_search_drafts_options",
     "patch_flask_create_url_adapter",
     "register_menu_entries",