We experienced an outage of the Wikimedia Foundation website on 11 June 2019. The cause was our host and our ability to resolve it was limited. We were able to put up a maintenance page on VIP's servers during the outage. However, the idea came up that we should prepare a similar maintenance page on our servers for the site in case something major happened with our host and we decided we needed to flip the WikimediaFoundation.org domain back to our servers immediately.
To be clear, this outage was the first for our sites with that host in several years. We have no reason to believe it will happen again soon. However, we would like to be prepared just in case.
We have a maintenance page in PHP format that we could flip to HTML easily. What is the best way to get that on the servers in a way that we could easily setup the WikimediaFoundation.org to point to if we had an urgent need to do so?