Introduce replication_connect_timeout configuration option

Currently, the max time box.cfg() may wait for connection to replicas to
be established is hardcoded to box.cfg.replication_timeout times 4. As
a result, users can't revert to pre replication_connect_quorum behavior,
when box.cfg() blocks until it connects to all replicas. To fix that,
let's introduce a new configuration option, replication_connect_timeout,
which determines the replication configuration timeout. By default the
option is set to 4 seconds.

Closes #3151