Add client for http4s library

[igor-vovk]

Hi! I don't know if there is space for another client, but it seemed appropriate for me to add it, since it's kinda mainstream client in cats-effect ecosystem (http4s/circe/cats-effect). I was kinda surprised not to find it, ended up implementing it, but got tired copying it between my projects where I use elastic4s.

If you think it's a good idea to add it, I will be happy to add tests in this PR as well. Thank you.