Backup History: save to remote server for backup in RO replica

[fmbiete]

Using the --history option registers the backup metadata in the local database.

When using replication (classic, ReplicaSet, Cluster...), the replica is in RO (or SRO). If we want to execute the backups in a replica (to reduce impact in primary) and save the backup metadata we run into issues. This create an errant gtid (replica in RO) or fails (replica in SRO).

This adds the option to save the backup metadata in a remote server. In the case of a replication setup, we would run xtrabackup in the replica, but save the backup metadata in the primary.

New xtrabackup options

• history-host: (string) the name of the MySQL server where we will save the backup metadata. Default to host
• history-port: (uint) the port of the MySQL server where we will save the backup metadata. Default to port
• history-user: (string) the name of the MySQL user that we will use to save the backup metadata. Default to user
• history-password: (string) the password for the MySQL user that we will use to save the backup metadata

[it-percona-cla]

All committers have signed the CLA.

[satya-bodapati]

Thank you for your contribution, @fmbiete! I have created https://perconadev.atlassian.net/browse/PXB-3327 to track this pull request.

I will review this soon(at max a week). If not, please remind me once.