Enhancements for workflows and CLI interface

[rhugonnet]

While editing the documentation (and slightly the workflows) in #852, I noted some things we can improve:

• The topo workflow expects a reference_elev subsection between inputs and path_to_elev, which is unexpected (and not really documented) because the workflow works on a single elevation input. We can probably remove, except if we intend to add support for multiple elevation data in the future?
• Having to_vcrs as input in topo/accuracy seems unnecessary: The sampling_grid argument already specifies which grid/CRS should be used when comparing both (reference or to-be-aligned). The vertical CRS being part of the CRS, it's transformed automatically during that step, so it never needs to be transformed during input reading with to_vcrs. The user should only be able to set or override the vertical CRS of the input data (set_vcrs).
• The accuracy workflow detailed description has two sub-tabs for reference/tba_elev within the tab inputs, but the description are exactly the same word-for-word for each. We could simplify by having those as a single page to avoid sub-tabs.

Some thoughts of global parameters that could be useful for users to access:

• The resampling during reprojection, or during point-grid interpolation (bilinear, cubic, etc). We could use the global GeoUtils parameters for this.
• The nodata_propagation behaviour during reprojection/interpolation.