Remove availability.html and all reference to it, since it is out of
date and has several broken links. The important content on
availability.html has been integrated into /index.html.

Replace availability.html with a dummy redirect page (to /index.html),
since it is still referenced from some other websites, most notably
http://www.highpoint-tech.com/home.htm .

PR: www/53429
Submitted by: myself
Approved by: ceri (mentor)