Fix building against Ubuntu Noble, Debian testing
- CMakeLists.txt: bump C++ standard to C++ 17
- tests/codec_test: fix -Wpessimizing-move warning
- tests/message_router_test: workaround weird -Wmaybe-uninitialized
- debian/: update debhelper compat to level 13
- debian/control: update metadata
- debian/control: prefer googletest over old pkg name google-mock
- debian/: adopt some packaging from Debian where appropriate