Refact(mixer): OO separation and encapsulation #65

src/aura_engine/base/api.py

src/aura_engine/channels.py

src/aura_engine/core/channels.py

src/aura_engine/core/client.py

src/aura_engine/core/mixer.py

src/aura_engine/engine.py

src/aura_engine/plugins/monitor.py

src/aura_engine/resources.py

src/aura_engine/scheduling/scheduler.py