[client-v2] Failover

[chernser]

Description

This issue is about adding failover support for client-v2. It should implement support of adding several endpoint that support same level of security (if first added endpoint is SSL and next ones should be, too) and all endpoint will use same configurations including credentials. Client will choose another node when "recoverable" error happens and will re-send request.

There are some limitations:

• Failover will be triggered when request is read only or failed on the start
• Each endpoint will use shared configuration