introduce filter_var to check for ENV boolean values within the config_local.php skeleton
introduce filter_var to check for ENV boolean values within the config_local.php skeleton

Adds flexibilty in how boolean values are allowed to be specified within the spryker
config. Now it behaves like the `is_true` function from common.inc.sh

claranet/spryker-base,claranet/spryker-base,claranet/spryker-base