full redo of auth middlewares

Changes:
- Oauth 2.0 providers code refactored into separate modules
- Swauth support in another separate module
- LiteAuth was refactored into token-related and auth-related code
- Added Swauth-LiteAuth integration
- Added generic Oauth 2.0 client code
- CORS handling (Swauth does not support CORS)
- Cookie support revamped
- Facebook Oauth2.0 provider added
- Quotas refactored to use generic auth mechanism, instead of relying on LiteAuth
- Accounting refactored to use generic auth mechanism, instead of relying on LiteAuth
- Support for invite codes added