Mysql configuration for stability

The following discussion from !173 (merged) should be addressed:

• @felix.huettner started a discussion: (+1 comment)

  can we ensure that the following settings are set inside the wsrep_provider_options of galera? gcomm.thread_prio=rr:2;gcs.fc_limit=160;gcs.fc_factor=0.8"

We should make the galera config configurable via cuelang and ensure that the mentioned parameters are set. They ensure that the cluster does not explode