docs: Misc cleanups

Moe the installation and contributor "guides" under 'install' and
'contributor', respectively, and remove some noise from the root index.

Change-Id: I96ef285dfa6624ca8bee79f2ec508eb2f9ff25b1
Signed-off-by: Stephen Finucane <stephenfin@redhat.com>

doc/source/contributing.rst

@@ -1,4 +0,0 @@
-============
-Contributing
-============
-.. include:: ../../CONTRIBUTING.rst

doc/source/contributor/index.rst

@@ -0,0 +1,5 @@
+============
+Contributing
+============
+
+.. include:: ../../../CONTRIBUTING.rst

doc/source/index.rst

@@ -1,10 +1,6 @@
-.. osc-placement documentation master file, created by
-   sphinx-quickstart on Tue Jul  9 22:26:36 2013.
-   You can adapt this file completely to your liking, but it should at least
-   contain the root `toctree` directive.
-
-Welcome to osc-placement's documentation!
-=========================================
+=============
+osc-placement
+=============
 
 .. We exclude the first few lines of the README since we don't need the badges
    (which don't render without extensions due to their SVG'ness) and we don't
@@ -19,8 +15,8 @@ Contents
 .. toctree::
    :maxdepth: 2
 
-   installation
-   contributing
+   install/index
+   contributor/index
    cli/index
    user/index