Add roughness calibration to D-Flow FM wrapper

[erikpelgrim]

Similar functionality to Sobek3SpatialDefinitionFile but with next differences:

DFlowFM_roughness.ini files has [Branch] sections instead of [BranchProperties] & [Definition] sections in Sobek3_roughness.ini
The [Branch] section contains all discharge levels, chainages and frictionValues

D-Flow FM also uses a separate file for observations points which is used to split branches by chainages over multiple exchange items.
Only the format of this file is slightly different:

Both use [ObservationPoint] sections but within those sections:

D-FlowFM uses name as where Sobek3 uses id