Fix: instead of uncommenting MySQL's `bind-address`, set `0.0.0.0` to allow all hosts.
Enh: allow to override `SHARD_KEY_MODULAR` parameter in *shard* and *shard_mysql* recipes.
Enh: a better way to detect the current hostname of the machine.
Fix: set shard key range based on shard key modular instead of hardcoding.
Enh: in *shard_mysql* open MySQL port only to CUBRID SHARD node.
Enh: allow to install CUBRID SHARD on all nodes for load balancing.
v2.3.1: improved *shard_mysql* recipe.