Add multi-source replication support in MaxScale

Add support for multi-source replication in Binlog Server

(1) Binlog Server should be able to replicate from multiple masters
Support CHANGE MASTER syntax for registering with multiple masters
CHANGE MASTER 'master-name' MASTER_HOST = 'master_host_ip', MASTER_USER = 'master_replication_user', MASTER_PASSWORD = 'password', MASTER_PORT = 3306;

(2) Binlog Server should be able to re-write the schema name
Support the same behavior as --replicate-rewrite-db option in MariaDB/MySQL slave

See example how it is done in a MariaDB/MySQL slave https://mariadb.com/blog/multisource-replication-how-resolve-schema-name-conflicts