MySQL example should provide for / allow for replication setups

**What would you like to be added**:
The ability to create a MySQL installation that leverages either native or Galera-based replication

**Why is this needed**:
Database replication is a key requirement for high-availability and workload partitioning (read/write nodes, etc).

If we are not going to provide an easy way to leverage native MySQL HA features, we should perhaps explore performance tests on how auto-replacement of db-nodes works vs. something like haproxy + galera.

Start by reading the linked KEP process before defining the enhancement scope. Compare the requested native MySQL and Galera-based replication options, including the suggested HAProxy and auto-replacement performance comparison. Done should mean a clearly chosen replication approach with an implementation plan and evidence for high availability and workload partitioning.

Written by the indexing model from the issue text.