MySQL example should allow for / provide for the use of xtrabackup

**What would you like to be added**:
The MySQL example should allow for / provide for the ability to use xtrabackup as the backup solution instead of mysqldump

**Why is this needed**:
Once a database grows beyond a certain size, xtrabackup becomes a more useful / performant backup and restore option. mysqldump remains a useful tool and should be readily available, but hot backups are very much a requirement for production workloads.

Start by locating the MySQL example and its current mysqldump backup and restore configuration. Review how the example could expose xtrabackup as an alternative while retaining mysqldump; done means the example supports both backup solutions for the stated production use case.

Written by the indexing model from the issue text.