Move RemotePlayer code to its own cpp/header

src/CMakeLists.txt

src/clientiface.cpp

src/content_sao.cpp

src/content_sao.h

src/environment.cpp

src/environment.h

src/localplayer.h

src/player.cpp

src/player.h

src/remoteplayer.cpp

src/remoteplayer.h

src/script/lua_api/l_object.cpp

src/script/lua_api/l_object.h

src/server.cpp

src/server.h