Uses xapian under the hood to index the contents, then makes it
searchable with a CGI binary on http://localhost:8080
We could in theory index every -doc output this way to get local
documentation search for the current system (similar to `man-db`).
Change-Id: I2588c8f100841cfbed570bb65d376b79747c06ee
Reviewed-on: https://cl.tvl.fyi/c/depot/+/12710
Tested-by: BuildkiteCI
Reviewed-by: Profpatsch <mail@profpatsch.de>
