Update benchmarking infrastructure and plan/organize perf testing

[ajcvickers]

As part of MQ and moving into EF Core 6.0, we should:

• Update performance infrastructure
• Decide where and how to add new perf coverage

Related issues:

• Cosmos: Add perf tests #14546
• Add perf tests that use buffering #18705
• Test CompiledQuery perf #18989
• Benchmarks: remove Sqlite from benchmark name #19874
• Benchmarks: make benchmarks always report results for one operation #25361
• Perf testing for many-to-many #21919