SSR support for results pages

**Is your feature request related to a problem? Please describe.**
Kind of. I run a website where I would love for some search results pages to rank in Google. Currently, these pages aren't being indexed by Google, presumably because the content isn't rendered server-side.

**Describe the solution you'd like**
I'd love to have the option for search results pages to be generated server-side, so that they would be picked up by search engines. I'm using NextJS, so having a way to combine Search UI and Next for SSR would be awesome.

**Describe alternatives you've considered**
The current alternative as described by @joemcelroy [on Slack](https://elasticstack.slack.com/archives/CNRDU3JAG/p1647360340262679?thread_ts=1647358451.050839&cid=CNRDU3JAG) would be interact with the Search API directly, instead of using Search UI.

**Additional context**
Add any other context or screenshots about the feature request here.

Start by reviewing how Search UI currently integrates with NextJS and how results pages are rendered. Define the SSR entry point and verify that representative search results pages are available to crawlers; the issue provides no named files or tests.

Written by the indexing model from the issue text.