Using Dart/Flutter URIs for resources

### Motivation

We use different API entries for specifying output folders and files and it seems we should study the Dart methodology for URI so we can be more consistent.

From module_services_api review:
I like this API because it's easy to understand, but should we be using some sort of URI object or something from Dart instead that supports referencing files, directories, and other weird stuff instead? I'm not sure the answer, genuine question.

### Desired solution

Consistent file resource specification for all output routines, including file directory specification, file name, extension, module name matching, etc.

### Alternatives considered

_No response_

### Additional details

_No response_

Start by reviewing the module_services_api and the existing output routines that accept folders and files. Compare their resource arguments with Dart's URI methodology, then define what a consistent specification must cover, including directories, file names, extensions, and module-name matching; done means all output routines use the agreed resource model.

Written by the indexing model from the issue text.