Fill out security page

[bdha]

https://illumos.github.io/docs/security/

[jclulow]

This was effectively vestigial (there was no real content) so I removed it from the first cut. We should synchronise with @danmcd about what to put on this page.

[danmcd]

Where/how do I get to this page from illumos.org/docs or even illumos.org? Or are those links also covered by this bug?

[bdha]

There was a vestigial page, but Josh pruned it before deploying the live site as it had no useful content.

You can see it here but it ain't much.

[danmcd]

It's enough to start with. Thanks.