docs: add some narrative docs to explain basic concepts

still needs a lot of work i'm sure..gotta start somewhere

docs/narr/cli/index.rst

@@ -0,0 +1,23 @@
+
+========================
+ Command Line Interface
+========================
+
+The primary way of using the import/export framework day to day is via
+the command line.
+
+WuttJamaican defines the ``wutta`` :term:`command` and WuttaSync comes
+with some extra :term:`subcommands <subcommand>` for importing to /
+exporting from the Wutta :term:`app database`.
+
+It is fairly simple to add a dedicated subcommand for any
+:term:`import handler`; see below.
+
+And for more general info about CLI see
+:doc:`wuttjamaican:narr/cli/index`.
+
+.. toctree::
+   :maxdepth: 2
+
+   builtin
+   custom