Improved startup and shutdown.

.vscode/launch.json

configuration/sample.engine.ini

configuration/supervisor/aura-engine-api.conf

configuration/supervisor/aura-engine-lqs.conf

configuration/supervisor/aura-engine.conf

configuration/systemd/aura-engine-api.service

configuration/systemd/aura-engine-liquidsoap.service

configuration/systemd/aura-engine.service

engine-api.py

engine-core.py

guru.py

modules/communication/redis/adapter.py

modules/core/startup.py

modules/scheduling/scheduler.py

run.sh