Enable tools to accept input args as IRPA files

### Request description

I want to be able to pass to `iree-run-module` and `iree-benchmark-module` input that is bfloat16. Numpy does not support this type.
I want to add support for consuming IRPA files. Would there be an objection supporting this?

There is also a [comment](https://github.com/iree-org/iree/blob/c04a0137383d7f4a2305bbbdc0058ac27f99cb41/runtime/src/iree/tooling/function_io.c#L602-L603) that we may add pluggable support for different input types. Maybe it is a good time to add that as well.

### What component(s) does this issue relate to?

Runtime

### Additional context

_No response_

Start by reading runtime/src/iree/tooling/function_io.c around lines 602-603 and inspect how iree-run-module and iree-benchmark-module currently consume inputs. Define the scope for IRPA inputs and whether pluggable input types should be included; done means both tools can consume bfloat16 input from IRPA files.

Written by the indexing model from the issue text.