Allow users to configure called test datasets within a Test Plan or a Test Execution

Currently, it is not possible to define a dataset with modular test parameters outside the scope of the test.

This is particularly useful if a modular is being called multiple times within the same test. Although we can define different datasets for each call within the parent test, it is not possible to redefine this information in the context of a Test Plan or a Test Execution.

A possible solution would be to allow users to define child datasets for tests with modular test calls.