Enhance server command limits

Enhance server command limits

This patch updates the limits for handling commands from a remote server:

 - "<user count> / 5 + <min>" using "<min>=10" during normal operation,
 - the above count multiplied with 5 while servers are syncing.

The intention is to a) make the limit dependent of the number of users
in the network (the more users, the more commands required to sync) and
b) to significantly rise this limit while servers are joining the network
to make the login and synchronization faster.