Consistency check of naming convention for data variables

[xldeltares]

Version checks

• I have checked that the issue still exists on the latest versions

Kind of issue

Docs are unclear

Documentation problem

For hydromt, a table has been created to harmonize the data variable naming conventions among different plugins. Upon filling in for hydromt_delft3dfm, it becomes clear that for hydromt_delft3dfm itself, data variable naming convention could still be improved for better consistency. It would be nice to do that altogether for 1D, 2D and 3D.

Link to the table is with @xldeltares.

[hboisgon]

Linked to this issue in hydromt that should be solved first: Deltares/hydromt#45