WIP Gaucho/GauchoAppl - Fix various linkage issues

Gaucho/GauchoAppl - Fix various linkage issues brought to light by the undefined behaviour sanitizer builds, e.g.

https://lhcb-nightlies.cern.ch/nightly/lhcb-sanitizers/build/361/

MakeFiles/GauchoLib.dir/src/StatusService.cpp.o:(.data.rel+0x98): undefined reference to `typeinfo for MonitorSvc'