Update C++ metrics service with our new metrics

[dbukki]

I added the bumpy road metric to the C++ metrics service, as requested in #714.
I added it as the third value to CppAstNodeMetricsType so that the order and values of the metrics here match that of CppAstNodeMetrics::Type.

I also changed the description of:

• McCabe to "Cyclomatic (McCabe) complexity of function". I added the fact that this is for functions explicitly, as we are also expected to have a version for types soon (Cyclomatic Complexity at Type Level for C++  #683).
• Lack of Cohesion: these are actually type-level metrics, not function-level metrics (Lack of Cohesion of Methods at Type Level for C++ #681).