Use std::shared_ptr, not boost::shared_ptr

ROOT6 cannot handle boost::shared_ptr due to the assembler code used in boost. Use std::shared_ptr instead. Use also with ROOT5 for commonality.
Most instances in the framework were modified, except for those in the event setup system, none of which are exposed to ROOT.  The changes outside the framework are the necessary adaptation to the framework changes.
Also, std::make_shared<> is used wherever possible, to reduce memory allocations.