Add emper::printInfo()

emper/Context.hpp

emper/Emper.cpp

emper/Emper.hpp

emper/lib/meson.build

emper/lib/template_util.hpp

emper/lib/util.cpp

emper/lib/util.hpp

tests/lib/TemplateUtilTest.cpp

tests/lib/UtilTest.cpp

tests/lib/meson.build