Tune additional Thanos flags

* Disable gossip cluster now that we're using discovery.
* Enable partial response in order to avoid hanging on slow storage
requests.
* Enable debug level logs on the storage servers.
2 jobs for <span class="ref-name">bjk/thanos_flags</span> in 3 minutes and 29 seconds
Status Job ID Name Coverage
  Test
passed #190631156
rspec

00:01:56

 
  Lint
passed #190631157
cookstyle

00:01:32