Helper class to detect if current instance is active or not.
The logic to detect if instance is active or inactive is based on the configuration in etcd under key
/vhosts/local-svc.leanix.net/deploy_current or
/vhosts/local-eam.leanix.net/deploy_current. In oder to use this
class you have to specify:
* ETCD_SERVER : the etcd server, e.g. '192.168.59.103:4001'
* CONTAINER_COLOR: 'green', 'blue' or 'white'
* VIRTUAL_HOST : the virtual host name e.g. 'local-eam.leanix.net' (default: local-svc.leanix.net)