feat: add install handler and related logic

- Mako is now a core dependency
- therefore no more 'email' extra
- add `get_install_handler()` method for app handler
- add `render_mako_template()` method for app handler
- add `resource_path()` method for app handler
- install handler thus far can:
  - confirm db connection
  - make appdir plus config/scripts:
    - wutta.conf
    - web.conf
    - upgrade.sh
  - upgrade db schema to create tables
  - from there web app can run, create admin user
- quick start docs now describe "generated code" option

docs/narr/install/quickstart.rst

@@ -2,6 +2,56 @@
 Quick Start
 ===========
 
+We have two varieties of "quick start" instructions:
+
+* :ref:`quick-start-generated`
+* :ref:`quick-start-manual`
+
+
+.. _quick-start-generated:
+
+From Generated Code
+-------------------
+
+Note that this section describes an app based on WuttaWeb (i.e. not
+just WuttJamaican).
+
+There is a tool to `generate new project code`_, on the Rattail Demo
+site.  Use it to download a ZIP file (e.g. ``poser.zip``) for your
+project.
+
+.. _generate new project code: https://demo.rattailproject.org/generated-projects/new/wutta
+
+Make a local :term:`virtual environment` for your project.
+
+Also make a new e.g. ``poser`` database in PostgreSQL (or MySQL).
+
+Unzip and install the source code to the virtual environment, then run
+the app installer:
+
+.. code-block:: sh
+
+   mkdir -p ~/src
+   unzip ~/Downloads/poser.zip -d ~/src
+
+   cd /path/to/venv
+   bin/pip install -e ~/src/poser
+   bin/poser install
+
+Assuming all goes well, you can run the web app with:
+
+.. code-block:: sh
+
+   bin/pserve --reload file+ini:app/web.conf
+
+And browse it at http://localhost:9080
+
+
+.. _quick-start-manual:
+
+From Scratch
+------------
+
 This shows the *minimum* use case, basically how to make/use the
 :term:`config object` and :term:`app handler`.
 
@@ -67,7 +117,7 @@ For more info see:
 .. _db-setup:
 
 Database Setup
-==============
+~~~~~~~~~~~~~~
 
 You should already have the package installed (see previous section).