* Complimentary to #3918
I think that we can use Poco::Mutex and Poco::FastMutex as wrappers for std::recursive_mutex and std::mutex instead of replacing
For using std::*mutexes switch on cmake-option POCO_ENABLE_STD_MUTEX
* add define POCO_ENABLE_STD_MUTEX to the Config.h
remove empty if-else from CMakeLists.txt
