Support for galera GTID consistency thru cluster. All nodes in cluster
should have same GTID for replicated events which are originating from cluster.
Cluster originating commands need to contain sequential WSREP GTID seqno
Ignore manual setting of gtid_seq_no=X.

In master-slave scenario where master is non galera node replicated GTID is
replicated and is preserved in all nodes.

To have this - domain_id, server_id and seqnos should be same on all nodes.
Node which bootstraps the cluster, to achieve this, sends domain_id and
server_id to other nodes and this combination is used to write GTID for events
that are replicated inside cluster.

Cluster nodes that are executing non replicated events are going to have different
GTID than replicated ones, difference will be visible in domain part of gtid.

With wsrep_gtid_domain_id you can set domain_id for WSREP cluster.

Functions WSREP_LAST_WRITTEN_GTID, WSREP_LAST_SEEN_GTID and
WSREP_SYNC_WAIT_UPTO_GTID now works with "native" GTID format.

Fixed galera tests to reflect this chances.

Add variable to manually update WSREP GTID seqno in cluster

Add variable to manipulate and change WSREP GTID seqno. Next command
originating from cluster and on same thread will have set seqno and
cluster should change their internal counter to it's value.
Behavior is same as using @@gtid_seq_no for non WSREP transaction.