Simplify the project

[dartpopikyardo]

Principles to follow:

• A module per service, e.g. customer-service - instead of 3+/service
• Discarded support for monolith - not important - that enables the module structure to be simpler
• Simpler, more sensible naming conventions - no command-side, query-side, ..., instead - e.g. customer-service
• Each service has an application.properties that defines some sensible defaults - simplifies the amount of configuration needed in docker-compose.yml