feat: add wutta top-level command with make-uuid subcommand

i think it only makes sense to have an "opinion" for command line
interface in this project, and we probably need more `wutta`
subcommands too but we'll see.

main motivation for this currently is to allow poser apps to define
their own CLI, in particular e.g. `poser install`

docs/narr/cli/builtin.rst

@@ -0,0 +1,41 @@
+
+Built-in Commands
+=================
+
+WuttJamaican comes with one top-level :term:`command`, and some
+:term:`subcommands<subcommand>`.
+
+It uses `Typer`_ for the underlying CLI framework.
+
+.. _Typer: https://typer.tiangolo.com/
+
+
+``wutta``
+---------
+
+This is the top-level command.  Its purpose is to expose subcommands
+pertaining to WuttJamaican.
+
+It is installed to the virtual environment in the ``bin`` folder (or
+``Scripts`` on Windows):
+
+.. code-block:: sh
+
+   cd /path/to/venv
+   bin/wutta --help
+
+Defined in: :mod:`wuttjamaican.cli`
+
+.. program-output:: wutta --help
+
+
+.. _wutta-make-uuid:
+
+``wutta make-uuid``
+-------------------
+
+Print a new universally-unique identifier to standard output.
+
+Defined in: :mod:`wuttjamaican.cli.make_uuid`
+
+.. program-output:: wutta make-uuid --help