Enable search on kernelci.org static website

The Hugo Docsy theme comes with a search feature in the documentation section. This didn't quite work at first so it was disabled in the settings, but now the documentation is growing and we're keeping this theme it would be worth enabling it again.

Start with the Hugo Docsy theme settings that disabled search and run the static documentation site locally. Re-enable the existing search feature, then verify that the documentation section exposes working search results in the generated site.

Written by the indexing model from the issue text.