Find dis2 solutions
Implements RAP-605. Given the path to ddf-pipeline's SOLSDIR folder, this adds steps that will:
- Automatically find the DIS2 solutions in npz format given the SOLSDIR directory.
- Convert them to H5parm format
- Merge them into a single H5parm
This eliminates the need for a user to do this manually and replaces the ddf_solset
parameter that previously took the H5parm from step 3.