swh-web fishes the save code now logs out of elasticsearch if available.

However, the way it's implemented currently depends on the availability of a given member of the elasticsearch cluster. There's a few issues with that, but most notably:

• requests depend on that member being available
• requests are done synchronously and make the (gunicorn) workers hang until an unspecified timeout
• there's no provision for failover.

It'd be nicer if these requests used an elasticsearch library which would wrap the failover mechanism (and possibly allow asynchronous requests as well?)