overview-manual: remove 'overview-manual' from filenames

All filenames duplicate the 'manual name', which is not needed, and
make all references longer than they should. Rename all files to be as
consise as possible, and fix all references

(From yocto-docs rev: 4f489a40bb00be018e419802a76fec9dbee3f255)

Signed-off-by: Nicolas Dechesne <nicolas.dechesne@linaro.org>
Signed-off-by: Richard Purdie <richard.purdie@linuxfoundation.org>

documentation/overview-manual/concepts.rst

@@ -40,7 +40,7 @@ section of the Yocto Project Development Tasks Manual.
 Following are some brief details on these core components. For
 additional information on how these components interact during a build,
 see the
-":ref:`overview-manual/overview-manual-concepts:openembedded build system concepts`"
+":ref:`overview-manual/concepts:openembedded build system concepts`"
 section.
 
 BitBake
@@ -1109,7 +1109,7 @@ the extensible SDK (eSDK):
 .. note::
 
    For more information on the cross-development toolchain generation,
-   see the ":ref:`overview-manual/overview-manual-concepts:cross-development toolchain generation`"
+   see the ":ref:`overview-manual/concepts:cross-development toolchain generation`"
    section. For information on advantages gained when building a
    cross-development toolchain using the do_populate_sdk task, see the
    ":ref:`sdk-manual/sdk-appendix-obtain:building an sdk installer`" section in

documentation/overview-manual/index.rst

@@ -10,10 +10,10 @@ Yocto Project Overview and Concepts Manual
    :caption: Table of Contents
    :numbered:
 
-   overview-manual-intro
-   overview-manual-yp-intro
-   overview-manual-development-environment
-   overview-manual-concepts
+   intro
+   yp-intro
+   development-environment
+   concepts
    history
 
 .. include:: /boilerplate.rst

documentation/overview-manual/intro.rst

@@ -28,7 +28,7 @@ The following list describes what you can get from this manual:
    Yocto Project source repositories, workflows using Git and the Yocto
    Project, a Git primer, and information about licensing.
 
--  :doc:`overview-manual-concepts` *:* This
+-  :doc:`/overview-manual/concepts` *:* This
    chapter presents various concepts regarding the Yocto Project. You
    can find conceptual information about components, development,
    cross-toolchains, and so forth.

documentation/overview-manual/yp-intro.rst

@@ -589,7 +589,7 @@ Project.
 .. note::
 
    For additional detail about the Yocto Project development
-   environment, see the ":doc:`overview-manual-development-environment`"
+   environment, see the ":doc:`/overview-manual/development-environment`"
    chapter.
 
 -  *Native Linux Host:* By far the best option for a Build Host. A