dev-manual, ref-manual, yocto-project-qs: Debian support added

Fixes [YOCTO #4912]

Throughout the manual set, various areas talk about the Linux
distributions we support and the required packages among other
items that are tied to a distro.  Debian had been missing except
from the list in the ref-manual that shows the releases we test
against.

I have attended to all areas where Debian needs to be mentioned
now.

Reported-by: Laszlo Papp <lpapp@kde.org>
(From yocto-docs rev: 2004567821add745d320106b0dc6cccb4f73b605)

Signed-off-by: Scott Rifenbark <scott.m.rifenbark@intel.com>
Signed-off-by: Richard Purdie <richard.purdie@linuxfoundation.org>

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

@@ -3496,7 +3496,7 @@
                         <literallayout class='monospaced'>
      service httpd reload
                         </literallayout>
-                        For Ubuntu, use the following:
+                        For Ubuntu and Debian, use the following:
                         <literallayout class='monospaced'>
      /etc/init.d/apache2 reload
                         </literallayout>

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

@@ -1537,7 +1537,7 @@
                     <filename>git send-email</filename> command.
                     <note>In order to use <filename>git send-email</filename>, you must have the
                     the proper Git packages installed.
-                    For Ubuntu and Fedora the package is <filename>git-email</filename>.</note></para>
+                    For Ubuntu, Debian, and Fedora the package is <filename>git-email</filename>.</note></para>
                     <para>The <filename>git send-email</filename> command sends email by using a local
                     or remote Mail Transport Agent (MTA) such as
                     <filename>msmtp</filename>, <filename>sendmail</filename>, or through a direct