Parts of the documentation about log offloading repeated itself.
I added a new "Failover Considerations" section that focuses on that
topic specifically. Therefore, other sections no longer need to show
multi-server configurations.
The new section contains recommendations about
log_retry_count and log_retry_interval values for failover
configurations as well.
Story: 2009876
Task: 44599
Change-Id: If71fce80329fe772c8248bc2eb4445ea15680c5d
911300d688