Consolidate admin guide and configuration guide

Both admin guide and configuration guide are targeting for the
same group of readers. There is no need to separate these two guides.
Move all contents under doc/source/admin to doc/source/configuration

Change-Id: I7560a8a52c2c4a23758dda75ae2979a68dd7c060

doc/source/admin/README.rst

@@ -1,7 +0,0 @@
-===============================================
-Zun Administration Documentation (source/admin)
-===============================================
-
-
-This directory is intended to hold any documentation that is related
-to how to run or operate Zun.

doc/source/admin/index.rst

@@ -1,15 +0,0 @@
-Administrator's Guide
-=====================
-
-Installation & Operations
--------------------------
-
-If you are a system administrator running Zun, this section contains
-information that should help you understand how to deploy, operate, and upgrade
-the services.
-
-.. toctree::
-  :maxdepth: 1
-
-  osprofiler
-  clear-containers

doc/source/configuration/index.rst

@@ -6,3 +6,5 @@ Sample Configuration File
 
     sample-config
     policy
+    osprofiler
+    clear-containers

doc/source/contributor/documentation.rst

@@ -92,7 +92,6 @@ as is documented in the ``README`` in each directory:
 .. toctree::
    :maxdepth: 1
 
-   ../admin/README
    ../cli/README
    ../configuration/README
    ../contributor/README

doc/source/index.rst

@@ -17,13 +17,6 @@ Welcome to Zun's documentation!
 Zun is an OpenStack Container service. It aims to provide an OpenStack API for
 provisioning and managing containerized workload on OpenStack.
 
-Admin Guide
-~~~~~~~~~~~
-.. toctree::
-   :maxdepth: 1
-
-   admin/index
-
 Contributor Guide
 ~~~~~~~~~~~~~~~~~
 .. toctree::