Add routes and functionality for inventory management, user management, worklogs, and settings

- Created a new Blueprint for main routes in `routes/__init__.py`.
- Implemented inventory listing and item management in `routes/inventory.py`.
- Added user listing and detail views in `routes/user.py`.
- Developed worklog listing and entry views in `routes/worklog.py`.
- Introduced search functionality across inventory, users, and worklogs in `routes/search.py`.
- Established settings management for brands, items, rooms, and functions in `routes/settings.py`.
- Enhanced helper functions for rendering headers and managing data in `routes/helpers.py`.
- Updated index route to display active worklogs and inventory conditions in `routes/index.py`.

routes/__init__.py

@@ -0,0 +1,5 @@
+from flask import Blueprint
+
+main = Blueprint('main', __name__)
+
+from . import inventory, user, worklog, settings, index, search