run benchmarks

[tachella]

This PR adds the run_benchmark function to this repo such that users can quickly evaluate their model on a given benchmark as

from deepinv_bench import run_benchmark
my_solver = lambda y, physics: ...  # your solver here
results = run_benchmark(my_solver, "benchmark_name")

@tomMoral is there an easy way to do this with benchopt? see todo in the PR :)