index of bnd is lost when reading an existing model

[DirkEilander]

When creating a model the index column of your locations from setup_waterlevel_forcing is used. However after reading this model again the index (and all other properties) are lost, These properties are not saved in the sfincs.bnd file but can be read from the bnd.geojson file. The dimension order of the forcing has also changed.

TODO:

• use the properties from the bnd.geojson file to update the index of bzs forcing in read_forcing
• transpose the dimensions to have time on the first dimension in read_forcing
• check if the same is true for src points

[roeldegoede]

Good observation! This indeed links to one of the discussion points of #114, where we also lose the original indices when setting up observation lines. Same holds for setup_observation_points. Let's try to fix those all at once.