Rewritten XSA status page, xsa.json

[George Dunlap <george.dunlap@xxxxxxxxx>]

Hey all,

Some of you may have noticed that xenbis.xenproject.org/xsa/ doesn't
currently list XSA-456.  This has prompted me to rewrite the perl code
which generates that area of the webpage into golang, which is much
easier for the current security team to understand and modify.  The
draft replacement is here:

https://xenbits.xenproject.org/people/gdunlap/xsa-draft/

In particular, if you use `xsa.json` for any purpose, let me know if
you have any issues.  If I don't hear any objections I'll replace the
website generation code on Wednesday.

Thanks,
 -George