[Migration] Update dashboard to process results from openxla-benchmark

Benchmark results uploaded from openxla-benchmark are a little different from iree-samples.

Here is the example from T5_LARGE_FP32_JAX benchmarks:

From iree-samples: https://gist.github.com/pzread/2be3b2db7c0ffa14518085f08e33b815
From openxla-benchmarks: https://gist.github.com/pzread/cf3e089d0a4e0d5c452aebc1df6dbc44

The major differences are:

- Changes in benchmark id and benchmark name
- Changes in some metadata values (e.g. `data_type` and `device` field)
- Changes in the format of `python_environment` field

I think the pain point will be changing the benchmark id, which means we might need a backfill of the historical data. We can still show new data in the dashboard first then backfill the previous data