Support Active-Active HA without LB

[Attila Fazekas]

Allow to configure multiple connection uri or host to the same data source.

The service should shuffle the the DB uri-s at startup, and try to use the first one first. Every new connection

This could eliminate the need of an LB layer between the services and DB -> better latency, less service.

Even tcp LB cannot guaranty you do not need to reconnect on server failure.
The main benefits of dedicated LB:
 - On planned server restart you cloud limit the number of logged connection issues, by disallowing new connection to the server which has scheduled downtime.
 - The LB can consider the number of existing connection when picking a backend server
 - When you would like to add a new DB saver (almost never happens), you do not need to change all servers config file.

Without LB.:
 - You do not need to mange and spent resources on a LB layer
 - Better latency
 - The services might connect to DB servers without a perfect balance, but if the HA setups main purpose is redundancy and
   not real load balancing it is not a real concern.

Similar solution is already possible with messaging.