Adding new ways for authorization

Files to change

• learn2rag/userui/auth/SOMETHING.py - add implementation of user login flow
• learn2rag/userui/auth/__init__.py::build_router - auth_routers - include the implementation there for it to show up in user UI
• learn2rag/pipeline/authorization_SOMETHING.py – add implementation of online filter check
• learn2rag/pipeline/authorization.py::_create_authorization_filter - add initialization of the filter check
• learn2rag/ui/templates/sources_add_SOMETHING.py - add fields for configuring data source