Benchmark runner convenience for "can I run X benchmark?"

[trexfeathers]

📰 Custom Issue

python bm_runner.py test_run my_benchmark

Is something we do a lot when writing a new benchmark.

Should automatically select the various things to speed stuff up like --quick and --attribute rounds=1 etcetera.

@pp-mo suggests forcing the use of an existing environment (-E argument), and also making that the DATA_GEN_PYTHON environment too. Would be easy enough to pass a path in as a argument or an env variable, could maybe limit it to just the name of a Conda environment?