How we do benchmarking

Is there a reason, beyond historical, that we use `ASV` over `pytest-benchmark` ?
Looking at the two tools, `pytest-benchmark` has 1.5x more stars and 8x greater usage (as measured by GH dependencies). Also `pytest-benchmark` integrates into our existing pytest framework so that this repo might pull tests directly from `astropy`'s test suite, using a `pytest` Mark (e.g. `pytest.mark.benchmark_only`).

Start by reviewing the existing ASV setup and the repository's use of pytest, then compare how pytest-benchmark could integrate with the astropy test suite through a benchmark-only mark. Done would require a maintainer decision on whether to retain ASV or pursue a migration, with the chosen rationale and scope documented.

Written by the indexing model from the issue text.