Port go package to universe to resolves #1553

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>

pkg/universe.dagger.io/go/test/data/hello/greeting/greeting.go

@@ -0,0 +1,7 @@
+package greeting
+
+import "fmt"
+
+func Greeting(name string) string {
+	return fmt.Sprintf("Hi %s!", name)
+}