Add search

[philrz]

As discussed in #4, my plans for having a single Search for both the Zed and Zui docs sites needs some help from the DocSearch team or starting a paid Algolia plan. Once we've heard back from DocSearch and decide a way forward, the next steps I'm aware of:

• Restore the Algolia config that was backed out in Drop Algolia search config on zui.brimdata.io for now #4
• Modify the crawler config on the Algolia site to include zui.brimdata.io, manually trigger a crawl, and make sure search works as we expect across both sites
• Set externalUrlRegex on zed-docs-site to "zui\\.brimdata\\.io"
• Uncomment the "Trigger Algolia Crawler" section in the deploy.yaml Action

[philrz]

Some initial steps for getting this working have been completed, but there's more left to do. Per brimdata/zed-docs-site#63, our DocSearch config has helpfully been modified by the folks at Algolia such that both zed.brimdata.io and zui.brimdata.io are now being crawled and a single index is being populated for both. However, the user-issued searches aren't actually working quite the way I'd want them to from the Zed site, and I can see if we enable search from the Zui site we'd have a similar problem in reverse. Therefore right now I'm trying to get that resolved. I've made a post on the Algolia community site that describes the problem in more detail.