[IMG282] add data_load function via param.ParametrizedFunction
- Original Gitlab Story: IMG282
This PR introduces the following changes
- add new backend function,
load_data
implemented as a parameterized function - corresponding unit test
Note: As indicated in the comments, the auto matching open-beam and dark-current files using embedded metadata cannot be implemented at this time as it requires a helper class that can handle the metadata in a more generic way.