[BITV]: create a server side switch for activation / deactivation a "Unified search" feature

"Unified search" feature is not accessible at the moment. A good decision would be to create a configurable parameter in a config file which can be enabled or disabled for every instance individually.

Please create a comment above this parameter in `config` file with a text: _this feature is not accessible and is not BITV confirm._

Thanks a lot!