initial commit for multi master changes

[utsab4u]

Anyone planning to use the multi master current needs to implement the following methods

               @Override
                protected boolean enableMultiMaster(){
                    return true; //default false
                }

                @Override
                protected int shardCount(){
                    return 3; //default numShards. Needs to be the total number of shardBundles required across all shards
                }

The current config looks like

  shards:
    - driverClass: org.mariadb.jdbc.Driver
      user: username
      password: password
      url: jdbc:mariadb:sequential://vip1/shard_1
      ..........
      ........
    - driverClass: org.mariadb.jdbc.Driver
      user: username
      password: password
      url: jdbc:mariadb:sequential://vip2/shard_2
      ..........
      ........

The new config would looks like

  shards:
    - driverClass: org.mariadb.jdbc.Driver
      user: username
      password: password
      url: jdbc:mariadb://vip1-1/shard_1, jdbc:mariadb:sequential://vip1-2/shard_1 
      ..........
      ........
    - driverClass: org.mariadb.jdbc.Driver
      user: username
      password: password
      url: jdbc:mariadb://vip2/shard_2 //not using multiple vips
      ..........
      ........