Allow TPCH tooling to create a combined result for easier processing by outside tools

[isidentical]

Is your feature request related to a problem or challenge? Please describe what you are trying to do.
Currently, we have to run each query individually for retrieving the benchmark results for it. This also applies to the results, where we have to actually create multiple files and then combine them later into a single one (summaries).

$ ./tpch benchmark datafusion --query 1 -o queries
$ ./tpch benchmark datafusion --query 2 -o queries
...

Describe the solution you'd like
If --query argument is not passed, I think we should be able to run everything at once and output a uniform summary.

Describe alternatives you've considered
Automating this with an external script might also be an option, but I think this version is cleaner.

Additional context
This should ideally also help on the path to a conbench task for TPCH, since we can now get a uniform result set.