Auth for sending events fixed

Error is now raised via req.error helper, which automatically adds already known info (method, request id), thus calls are terser.
Client's Error communicates request id, if received from server.
exc_info made explicit everywhere. Automatic exc_info gathering sometimes returned bogus info about unrelated exception from far before.

Logging now automatically adds this request id + called method into all log messages.

Added Request class for request data shared among instances. Will simplify error handling and logging

Server is now less revealing in error messages to clients (local logging is still as verbose as requested)

Fixed multiple HTTP args encoding/parsing, store_event now uses SQL placeholders, more robust fetching of cat/tag in store_event, simplified map_id usage

Now auth/auth actually works. Now uses services on many places, where clients was used (and didn't work)

Fixed for now: /opt/warden_server_3/warden_server.py:427: Warning: Field 'request' doesn't have a default value

Mapping id updated
Category 'test' supported
Filtering by parent category

Authorization
Authentication