Change XML Connect Pool option to Cluster Connect

[sm-shaw]

Is your feature request related to a problem? Please describe.
The XML Connect Pool option could be named better as the pool of connections is nearly always used for cluster testing with multiple endpoints.

Describe the solution you'd like
Change the naming under the GUI and CLI from connect pool to cluster connect. eg mysql_connect_pool dict setting would be mysql_cluster_connect.

Describe alternatives you've considered
An additional option is to also include a user configurable location for the cluster connect file. The default location would be the config/clusterconnect directory, however the GUI & CLI would include an additional option. In the GUI this is grey out until cluster connect is selected. This then makes the option much clearer that the user needs to define multiple end-point connections in a separate file.

Additional context
The additional option would go at the end as shown here.

Update should be for all databases.