dev-manual, profile-manual, ref-manual: Updates to remove meta-toolchain

The term "meta-toolchain" is legacy now.  I went through and removed
its use except for where it appears still as output from the
oe-init-build-env script.

(From yocto-docs rev: 1cc134060459278997d57f1293f54091c5404d85)

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

documentation/dev-manual/dev-manual-common-tasks.xml

@@ -5932,7 +5932,6 @@
          core-image-minimal
          core-image-sato
          meta-toolchain
-         adt-installer
          meta-ide-support
             </literallayout>
         </para>

documentation/dev-manual/dev-manual-newbie.xml

@@ -636,8 +636,6 @@
                         <listitem><para>A relocatable toolchain used outside of
                             BitBake by developers when developing applications
                             that will run on a targeted device.
-                            Sometimes this relocatable cross-development
-                            toolchain is referred to as the meta-toolchain.
                             </para></listitem>
                     </itemizedlist>
                 </para>
@@ -666,10 +664,6 @@
                 "<ulink url='&YOCTO_DOCS_BSP_URL;#bsp-layers'>BSP Layers</ulink>"
                 section in the Yocto Project Board Support Packages (BSP)
                 Developer's Guide.</para></listitem>
-            <listitem><para id='meta-toolchain'><emphasis>Meta-Toolchain:</emphasis>
-                A term sometimes used for
-                <link linkend='cross-development-toolchain'>Cross-Development Toolchain</link>.
-                </para></listitem>
             <listitem><para id='metadata'><emphasis>Metadata:</emphasis>
                 The files that BitBake parses when building an image.
                 In general, Metadata includes recipes, classes, and