ask.o.o is dead, remove it

Remove ask.o.o references, replace one place with a link to Stack
Overflow.

ask.o.o is read-only now and unmaintained.

Change-Id: If2967a0d960002cc8fb80e6b40f28e42cebce552

doc/common/app-support.rst

@@ -57,21 +57,6 @@ documentation:
 
 *  `Documentation Contributor Guide <https://docs.openstack.org/doc-contrib-guide/>`_
 
-ask.openstack.org
-~~~~~~~~~~~~~~~~~
-
-During the set up or testing of OpenStack, you might have questions
-about how a specific task is completed or be in a situation where a
-feature does not work correctly. Use the
-`ask.openstack.org <https://ask.openstack.org>`_ site to ask questions
-and get answers. When you visit the `Ask OpenStack
-<https://ask.openstack.org>`_ site, scan
-the recently asked questions to see whether your question has already
-been answered. If not, ask a new question. Be sure to give a clear,
-concise summary in the title and provide as much detail as possible in
-the description. Paste in your command output or stack traces, links to
-screen shots, and any other information which might be useful.
-
 The OpenStack wiki
 ~~~~~~~~~~~~~~~~~~
 

doc/doc-contrib-guide/source/doc-bugs.rst

@@ -64,7 +64,7 @@ Bugs differ depending on:
    problems with your environment, and you are following the installation
    tutorials, seek assistance from the relevant team and operations
    specialists on IRC,
-   `ask.openstack.org <https://ask.openstack.org/en/questions/>`_
+   `Stack Overflow <https://stackoverflow.com/questions/>`_
    or the OpenStack mailing list.
 
    For more information about the relevant IRC channels, see the

www/templates/header.tmpl

@@ -80,7 +80,6 @@ data-toggle="collapse" data-target="#bs-example-navbar-collapse-1">
                         <ul class="dropdown-menu dropdown-hover" role="menu" aria-labelledby="dropdownMenuEvents">
                             <li role="presentation"><a role="menuitem" tabindex="-1" href="https://www.openstack.org/marketplace/training/">Training</a></li>
                             <li role="presentation"><a role="menuitem" tabindex="-1" href="https://www.openstack.org/coa/">Get Certified</a></li>
-                            <li role="presentation"><a role="menuitem" tabindex="-1" href="//ask.openstack.org">Ask a Technical Question</a></li>
                             <li role="presentation"><a role="menuitem" tabindex="-1" href="//superuser.openstack.org">Superuser Magazine</a></li>
                             <li role="presentation"><a role="menuitem" tabindex="-1" href="https://www.openstack.org/videos/">Summit Videos</a></li>
                             <li role="presentation"><a role="menuitem" tabindex="-1" href="https://www.openstack.org/analysts/">Analyst Reports</a></li>