Split docs into siteadmin and pluginwriter guides

* create initial bits for plugin writer's guide
* move siteadmin stuff to site administrator's guide
* rework index.rst to support multiple guides
* tweak some text
* move files into subdirectories

I verified that this still works with html and texinfo build targets.
There's still a lot of work to do, but this is a good start.

docs/source/siteadmin/configuration.rst

@@ -0,0 +1,129 @@
+.. MediaGoblin Documentation
+
+   Written in 2011, 2012 by MediaGoblin contributors
+
+   To the extent possible under law, the author(s) have dedicated all
+   copyright and related and neighboring rights to this software to
+   the public domain worldwide. This software is distributed without
+   any warranty.
+
+   You should have received a copy of the CC0 Public Domain
+   Dedication along with this software. If not, see
+   <http://creativecommons.org/publicdomain/zero/1.0/>.
+
+.. _configuration-chapter:
+
+========================
+Configuring MediaGoblin
+========================
+
+So!  You've got MediaGoblin up and running, but you need to adjust
+some configuration parameters.  Well you've come to the right place!
+
+
+MediaGoblin's config files
+==========================
+
+When configuring MediaGoblin, there are two files you might want to
+make local modified versions of, and one extra file that might be
+helpful to look at.  Let's examine these.
+
+mediagoblin.ini
+  This is the config file for MediaGoblin, the application.  If you want to
+  tweak settings for MediaGoblin, you'll usually tweak them here.
+
+paste.ini
+  This is primarily a server configuration file, on the Python side
+  (specifically, on the WSGI side, via `paste deploy
+  <http://pythonpaste.org/deploy/>`_ / `paste script
+  <http://pythonpaste.org/script/>`_).  It also sets up some
+  middleware that you can mostly ignore, except to configure
+  sessions... more on that later.  If you are adding a different
+  Python server other than fastcgi / plain HTTP, you might configure
+  it here.  You probably won't need to change this file very much.
+
+
+There's one more file that you certainly won't change unless you're
+making coding contributions to mediagoblin, but which can be useful to
+read and reference:
+
+mediagoblin/config_spec.ini
+  This file is actually a specification for mediagoblin.ini itself, as
+  a config file!  It defines types and defaults.  Sometimes it's a
+  good place to look for documentation... or to find that hidden
+  option that we didn't tell you about. :)
+
+
+Making local copies
+===================
+
+Let's assume you're doing the virtualenv setup described elsewhere in this
+manual, and you need to make local tweaks to the config files. How do you do 
+that? Let's see.
+
+To make changes to mediagoblin.ini ::
+
+    cp mediagoblin.ini mediagoblin_local.ini
+
+To make changes to paste.ini ::
+
+    cp paste.ini paste_local.ini
+
+From here you should be able to make direct adjustments to the files,
+and most of the commands described elsewhere in this manual will "notice"
+your local config files and use those instead of the non-local version.
+
+.. note::
+
+   Note that all commands provide a way to pass in a specific config
+   file also, usually by a ``-cf`` flag.
+
+
+Common changes
+==============
+
+Enabling email notifications
+----------------------------
+
+You'll almost certainly want to enable sending email.  By default,
+MediaGoblin doesn't really do this... for the sake of developer
+convenience, it runs in "email debug mode".
+
+To make MediaGoblin send email, you need a mailer daemon.
+
+Change this in your ``mediagoblin.ini`` file::
+
+    email_debug_mode = false
+
+You should also change the "from" email address by setting
+``email_sender_address``. For example::
+
+    email_sender_address = "foo@example.com"
+
+If you have more custom SMTP settings, you also have the following
+options at your disposal, which are all optional, and do exactly what
+they sound like.
+
+- email_smtp_host
+- email_smtp_port
+- email_smtp_user
+- email_smtp_pass
+
+
+All other configuration changes
+-------------------------------
+
+To be perfectly honest, there are quite a few options and we haven't had
+time to document them all.
+
+So here's a cop-out section saying that if you get into trouble, hop
+onto IRC and we'll help you out::
+
+    #mediagoblin on irc.freenode.net
+
+
+Celery
+======
+
+We should point to another celery-specific section of the document
+actually :)