config: activation_deadline new parameter in config yaml

Added new parameter in the config file - activation deadline

This patch allows to configure parameter activation_deadline for each instance in the configuration yaml. By default, the value set to 2 * 60 * 60 = 7200 sec (2 hours) which defines the maximum time that instance will wait to be activated and join a cluster. If the activation doesn't occur within this period the instance will shut down.