Europa: docker: split in smaller files

Signed-off-by: Solomon Hykes <solomon@dagger.io>

europa-universe/docker/push.cue

@@ -0,0 +1,31 @@
+package docker
+
+import (
+	"dagger.io/dagger"
+	"dagger.io/dagger/engine"
+)
+
+// Upload an image to a remote repository
+#Push: {
+	// Destination ref
+	dest: #Ref
+
+	// Complete ref after pushing (including digest)
+	result: #Ref & _push.result
+
+	// Registry authentication
+	// Key must be registry address
+	auth: [registry=string]: {
+		username: string
+		secret:   dagger.#Secret
+	}
+
+	// Image to push
+	image: #Image
+
+	_push: engine.#Push & {
+		dest:   dest
+		input:  image.rootfs
+		config: image.config
+	}
+}