documentation: Re-org for "closer-look" chapter

Fixes [YOCTO #11630]

The ref-manual needs expansion for the old "closer-look" chapter.
This chapter previously held a detailed look at what happens when
a user uses the YP to develop something.  Now, the chapter needs
to also contain YP development environment concepts (e.g. open-
source philosophy, etc.), which are coming from the dev-manual.

Because of this, I renamed the "closer-look.xml" chapter to be
"ref-development-environment.xml".  I also renamed the larger
section that was formerly the entire chapter into its own section
named "Development Concepts".

Both these changes caused a few links to break.  I fixed all the
links from within the various manuals so they would find appropriate
targets.

I did some re-writing for introductory material to introduce the new
chapter and the section on "Development Concepts".

A new file ("ref-development-environment.xml") was added by basically
renaming the "closer-look.xml" chapter.  And, the tracking for
"closer-look.xml" was deleted.

(From yocto-docs rev: e37806474578b4f0ed137f64d68a39a17ab60644)

Signed-off-by: Scott Rifenbark <srifenbark@gmail.com>
Signed-off-by: Richard Purdie <richard.purdie@linuxfoundation.org>

documentation/ref-manual/technical-details.xml

@@ -55,8 +55,8 @@
         Following are some brief details on these core components.
         For additional information on how these components interact during
         a build, see the
-        "<link linkend='closer-look'>A Closer Look at the Yocto Project Development Environment</link>"
-        Chapter.
+        "<link linkend='development-concepts'>Development Concepts</link>"
+        section.
     </para>
 
     <section id='usingpoky-components-bitbake'>