Allow overriding the default naming scheme for containers and other entities

[EuleMitKeule]

Description

I would love to have the option to declare a custom default naming scheme for every service in my docker-compose.yml file. Since I don't like having the project/directory name prefix contained in my services, right now I have to specify the container_name element for every service I create like this:

services:
  foo:
    image: ubuntu
    container_name: foo
  bar:
    image: nginx
    container_name: bar

This could be accomplished by allowing the user to specify a top level element like this or something similar to it:

naming_scheme: no-prefix

services:
  foo:
    image: ubuntu
  bar:
    image: nginx

[AhmedGrati]

/assign