Definition are now split in their own file.
`#Image` is a simple base image to set up a go container
`#Container` is a standalone environment to execute go command, any go command
should use this definition.
It shares `docker.#Run` fields to easily maintains this definition.
`#Build` and `#Test` are high level definition that use `#Container` to
execute common go operation in a CI.
Those definitions are tested with a simple greeting package.
Signed-off-by: Vasek - Tom C <tom.chauveau@epitech.eu>
