Add image role, support logging in to registries

roles/container/meta/argument_specs.yaml

@@ -7,10 +7,6 @@ argument_specs:
         description: Name of the container. Must be unique within a host.
         type: str
         required: true
-      container_image:
-        description: "The image to run in the container, in FQIN format (registry/imagename:tag)"
-        type: str
-        required: true
       container_command:
         description: Command to start the container with.
         type: list
@@ -23,6 +19,27 @@ argument_specs:
         required: false
         default: ""
 
+      container_image:
+        description: "The image to run in the container, in FQIN format (registry/imagename:tag)"
+        type: str
+        required: true
+      container_image_creds:
+        description: Credentials used to authenticate with the registry
+        type: dict
+        required: false
+        default:
+          username: ""
+          password: ""
+        options:
+          username:
+            description: Username
+            type: str
+            required: true
+          password:
+            description: Password
+            type: str
+            required: true
+
       container_mounts:
         description: List of bind mounts or volumes to be mounted inside the container.
         type: list