Add `pydra.compose.shell.fields.Out.finder` field to permit glob or regexes

[tclose]

What would you like changed/added and why?

• Auto-convert strings to default glob or regex (not sure which would be better, maybe glob) to a callable function that performs the glob

What would be the benefit? Does the change make something easier to use?

Streamlines a common basic use cases where the callable is used just to locate a generated file within the output directory. Would allow for these cases to be unstructured/structured to dictionaries that can be written to JSON/YAML.