Ability to configure benchmark class name in outputs

An individual benchmark method's name can be overridden for output purposes via the Description property on BenchmarkAttribute (see #1243 for a related issue on this). However, there doesn't seem to be a way to do the same for the entire class.

My use case: we have a superclass of benchmarks being extended for different databases, so an abstract OpenConnectionBenchmarks class gets extended by SqliteOpenConnectionBenchmarks. However, in the outputs (CSV going into a database) it's desirable to have OpenConnectionBenchmarks, as the database is tracked elsewhere.