set up v5-archive.patternfly.org

[nicolethoen]

Information about how to do this can be found in the Major Release Development process doc under the To set up/preserve the website for the old version heading

ultimately, the v5 branch in org should be publishing directly to the v5-archive site automatically each time code merges into that branch.

[kmcfaul]

v5-archive.patternfly.org is live
We can set up auto-pushing to the site from the v5 branch later on if needed (will be manually pushed until then).