[Error] Default container image and name not overridable from configuration files

**Describe the bug** `container_image` and `container_name` values, when provided in the config files, should set the default values to be used when creating a container. Instead, in Distrobox v2, those values are hardcoded **To Reproduce** Add this to your config file: ```ini container_image_default="myimage" container_name="mybox" ``` and run ``` distrobox create --dry-run ``` **Expected behavior** Create a container with name `mybox` from image `myimage`. Instead, hardcoded values are used.