Add option to wrap benchmark target command

[bheisler]

Criterion.rs benchmarks support a --profile-time option for doing profiling. However, cargo bench offers no way to run the benchmarks in a profiler, so users have to do that manually.

cargo-criterion could allow the user to provide a command template. For example:
cargo criterion --run-with 'perf record -o %TARGET%-perf.data -g %ARGS%' -- --profile-time 120 my_benchmark_name

This would replace %TARGET% with the benchmark target name and %ARGS% with the benchmark target executable and its arguments, then invoke the resulting command.