feat(app-user): userManagement service scaffolding

[imione]

• create user-management application
• add userModule
• add database configuration
• add configModule & refactor database config using configModule
• add terminus for healthcheck endpoint
• add graceful shutdown

[imione]

MikroOrmModule disconnects database in OnApplicationShutdown hook

• https://stackoverflow.com/questions/62033627/how-to-tear-down-mikroorm-in-nestjs
• Close the connection when app is being shut down dariomncs/nestjs-mikro-orm#10

At the mo, graceful shutdown doesn't need to be implemented.
And if other infrastructures which are managed in lifecycle hook, they woud be better wrapped in specific module and managed into the module.

So, I won't add graceful shutdown at this time.