USS folder members filtering

[KUGDev]

Is your feature request related to a problem? Please describe.
After #342 is implemented, make the same functionalitym but for a USS part.

Describe the solution you'd like
With a dataset members filtering feature, there is a well-defined solution on the z/OSMF REST API side: the only thing you need to specify is a pattern query parameter during members listing. In a USS part the first thing needed is to fetch the contents of a folder, and then the filtering may occur.

Describe alternatives you've considered
None at the moment (more specific path / sorting).