Refined 2-DC deployment solution (#1098)
Refined 2-DC deployment solution (#1098)

Changed all references of "synchronization" to "replication", because it's more accurate for 2DC + binlog deployment. (Synchronization implies data is replicated in both direction, which is not the case here, that's why replication is more accurate.)
pingcap/docs,pingcap/docs,pingcap/docs