Micro-framework

Extensions setup and start order adjusted to: from the inner extensions to the outer.

That might prevent some failure due to an extension expecting of it's composite extension being already setup/start.

Kombu Connections heartbeats are now configurable through AMQP_HEARTBEAT configuration.

Fix error that was causing the worker to freeze when some connection error caused Kombu to reconnect.

Fix error of worker's event loop not properly closing

Fixes regarding dependency injection to asyncio functions.