Add HOST_LABEL_<label> macro to BI search

[jwiederh]

General information

Add possibility to use host labels in the BI Search, making BI way more powerful and dynamic in large environments. Existing BI-configurations are not affected.

All host labels of the found hosts will be available as a macro.

E.g. with the label customer/location:berlin the label value can dynamically be accessed (berlin in this case) via $HOST_LABEL_customer/location$.