Create initial setup for Scheduler such location of DAGs, proto files etc. and docker configuration so we can start implementing DAGs for our services.

Notes:

• docker setup docs
• as we just use it as scheduler we would like to have it as a single instance, they have a good example of CeleryExecutor but we want to use LocalExecutor so we can run everything in single instance
• also would like to avoid using puckel/docker-airflow image if possible and use apache/airflow
• need to research if we can just run everything using single container