Added prominent warning to com.openexchange.hazelcast.network.symmetricEncryp tion setting that hints to possible unstable Hazelcast cluster behavior for high load scenarios

# Enables or disables symmetric encryption. When enabled, the entire
# communication between the hazelcast members is encrypted at socket level.
# Ensure that all symmetric encryption settings are equal on all
# participating nodes in the cluster. More advanced options (including
# asymmetric encryption and SSL) may still be configured via the
# hazelcast.xml file, see instructions on top of this file. Defaults to
# false.
#
# /!\ ---==== Additional note ====--- /!\
# If symmetric encryption is enabled, it might have impact on Hazelcast
# cluster stability. Hazelcast nodes start loosing cluster connectivity under
# high load scenarios
#
com.openexchange.hazelcast.network.symmetricEncryp tion=false