replication: Support MySQL Group Replication

[ShelwinSu]

[dveeden]

MGR == MySQL Group Replication

https://dev.mysql.com/doc/refman/8.4/en/group-replication.html

Note that GR (as it is also called) is one of the parts of InnoDB Cluster.

Reading the binary logs from a group member should work.
Not sure there is anything else related to GR that we should support.
But let's do some tests with a GR setup and make sure binlogs work.

This can be useful for setting this up: https://dev.mysql.com/doc/mysql-shell/8.4/en/setting-up-innodb-cluster-and-mysql-router.html