Support for MySQL/MariaDB Galera Clusters [DBZ-4323]

Migrated from [DBZ-4323](https://issues.redhat.com/browse/DBZ-4323)

The request is specifically for Galera and MariaDB but it wouldn't hurt to potentially cover MySQL as well.

Galera provides for primary / primary database nodes. This means that each node is taking updates at the same time and synching those changes with the other primary nodes.

Typically CDC solutions monitor one of the nodes in the Galera cluster and take the transactions from that log. The question is can we support Galera MariaDB cluster so that in the event of that node failing, we will auto connect to one of the other primaries and take the events from there.

fyi, my investigation so far show's that Galera only has limited support for GTID's and doesn't use binlog as it has its own synchronisation processes.

Is there potentially a solution whereby we have each node in the cluster connected to Debezium and each instance works of its own binlog. I can't say I understand what goes on at this level of the DB though...

Start by investigating how Galera synchronizes primary nodes, including its GTID and binlog limitations, and how Debezium currently consumes MySQL or MariaDB transaction logs. Define what failover between nodes and event continuity should mean, then validate whether a workable support approach exists for Galera clusters.

Written by the indexing model from the issue text.