Wan2skeaf.jl is creating unnecessary bxsf files that are then stored in AiiDA database as RemoteData nodes

[npaulish]

When separating the initial bxsf into single band files for SKEAF, it would be more efficient to write only the ones that are necessary (only for the bands that cross Fermi energy)

• Make sure to pass the user defined Fermi energy from the SKEAF parameters and decide accordingly which files to write

Important: If custom Fermi energy needs to be passed both to Wan2skeafCalculation and SkeafCalculation it should be an input to the workchain. Otherwise, e.g. if someone specifies a shifted Fermi energy only for SKEAF, wan2skeaf writes the bxsf files for only for the bands that cross the original Fermi level and the resulting frequencies will miss the contribution from the other bands crossing the new Fermi level.