Merge branch 'bartgol/eamxx/vert-remapper-refactor' (PR #6770)

In view of unifying the "dataset interpolation" implementations across eamxx, this PR makes the VerticalRemapper a bit more general. Namely:

- can be constructed from two existing grids (as opposed as assuming tgt grid is from map file);
- can handle "P0" and "Masked" extrapolation (the former does constant extrapolation, the latter sets extrapolated value to a constant mask value)
- can do different extrapolations at top and bottom of the column (but same extrapolation type across all columns)
- can handle 1d as well as 2d pressure profile, for both source and target pressure