ghost2zola: migrate a ghost blog to zola

Preparation

Usage

``` USAGE: ghost2zola [OPTIONS]

FLAGS: -h, --help Prints help information

-V, --version
        Prints version information

OPTIONS: --prefix Relative prefix within the archive

        In cases where the archive contains only a single blog, this is not necessary. When the archive contains
        several blogs, this can be set to any distinct prefix winnowing the selection to a single selection.

        If you're not sure what prefixes might be available, consider using the `find_ghost_db` tool.

ARGS: Path to a possibly-compressed tar archiving a ghost blog

<extract-path>
        Path to the base directory into which the ghost blog should be expanded.

        Normally, this is the `content/blog` directory of your zola installation.

```