Fix cmake to defein ROS_DISTRO and HUMBLE

[felixf4xu]

this is to fix #70

The main problem of that issue is that ROS_DISTRO was incorrectly defined as string not value (like 1 2 3), so many lines of code was actually not compiled.

Then the macro is defined correctly and then some code becomes redundant, so both rmw_ecal_dynamic_cpp/src/rmw/features.cpp and rmw_ecal_proto_cpp/src/rmw/features.cpp are deleted, shared code of rmw_ecal_shared_cpp/src/features.cpp is used instead.

After this PR, #70 is fixed but rmw_ecal_proto_cpp still does not run because of another issue, which will be reported later.