Provide a `textual` based terminal user interface for the command centre

A completely unnecessary but cool request but following from #13 working so nicely and @textualize offering cool libraries like [trogon](https://github.com/Textualize/trogon) and [textual](https://github.com/Textualize/textual) I thought would't it be nice to provide an additional terminal based interface which isn't exactly a CLI but not a traditional GUI.

Moreover this will extend out Python skills on the CLI and allow us to value add the library.

The *why* of this request really is around bringing richer CLI tools for the Gallagher ecosystem.

Note that this request and the CLI should be additional poetry installables. The API client should be a product of its own.